This paper aims at demonstrating that an acceptable level of performance as a group facilitator can be achieved byhospitality industry managers in a 35-hour course, to a maximum of fourteen trainees, experienced in gr...This paper aims at demonstrating that an acceptable level of performance as a group facilitator can be achieved byhospitality industry managers in a 35-hour course, to a maximum of fourteen trainees, experienced in groupleadership but not in small-group facilitation or large-group coordination. Based on a six-step model fororganizational intervention, the course was run in co-facilitation, using the effect of demonstration, modelling, andobservation to improve performance at individual level. The course represents a mix of organizational behaviourand human resources management that has proved to be effective in preparing managers to improve organizationalinnovation and accelerate change in companies. Each step produced outputs, namely three innovation projects.Participants rated the course in every item of an extensive questionnaire as Good and Very Good, except theintroduction (pre-consult), which was considered “too theoretical”. Therefore, the course model proved to beadequate for the preparation of managers as coaches for organizational innovation in the hospitality industry. As tofuture developments, they will have to do mostly with the functioning of a matrix structure in the hospitality industry,so that the whole approach may have a full impact on the company.展开更多
The paper puts forward a method on controlling the AM-OLED panel to display image with high gray scale levels. It also gives an ASIC design sample to implement this method. A twenty sub-fields scan scheme has been tak...The paper puts forward a method on controlling the AM-OLED panel to display image with high gray scale levels. It also gives an ASIC design sample to implement this method. A twenty sub-fields scan scheme has been taken into use in the chip to display 256 gray scale levels on a QVGA resolution AM-OLED display screen. The functions of image scaling and rotating have also been implemented for multiply application. The simulation and chip test result show that the chip design has met the design requirements.展开更多
The oxidative desulphurization process of coal with different metamorphism degrees treated by an air-steam mixture has been studied.It has been shown that the pyrite present in black coal and anthracite is oxidized wi...The oxidative desulphurization process of coal with different metamorphism degrees treated by an air-steam mixture has been studied.It has been shown that the pyrite present in black coal and anthracite is oxidized with the sulphur dioxide formation,and the process chemical mechanism does not depend on the quality of organic matter.The medium-metamorphized coal,capable of turning into a plastic state and cake in the range of investigated temperatures(350~450 ℃),is desulphurized with the greatest difficulty.The chemical mechanism dealing with the transformations of pyritic sulphur present in brown coal differs from similar processes taking place in black coal and anthracite,because FeS2 is converted with hydrogen sulphide formation at desulphurization.展开更多
Nacre, or mother-of-pearl, is a kind of composites of aragonite platelets sandwiched between organic materials. Its excellent mechanical properties are thought to stem from the micro architecture that is traditionally...Nacre, or mother-of-pearl, is a kind of composites of aragonite platelets sandwiched between organic materials. Its excellent mechanical properties are thought to stem from the micro architecture that is traditionally described as a 'brick and mortar' arrangement. In this paper, a new microstructure, referred to as mineral bridge in the biomineralization, is directly observed in the organic matrix layers (mortar) of nacre. This is an indication that the organic matrix layer of nacre should be treated as a three-dimensional interface and the micro architecture of nacre ought to be considered as a 'brick-bridge-mortar' structure rather than the traditional one. Experiments and analyses show that the mineral bridges not only improve the mechanical properties of the organic matrix layers but also play an important role in the pattern of the crack extension in nacre.展开更多
To explore the differences in mechanical behavior of nacre between shells that live in different water depths,the microstructures,phase composition and related mechanical properties of nacre under indentation,three-po...To explore the differences in mechanical behavior of nacre between shells that live in different water depths,the microstructures,phase composition and related mechanical properties of nacre under indentation,three-point bending and shear tests in deep-sea Nautilus and freshwater Cristaria plicata shells were systematically investigated.It is found that the nacreous structure in Nautilus shell exhibits an outstanding combination of high strength and high toughness compared with that in C.plicata shell,attributing to its larger aspect ratio of platelet and interfacial shear resistance.Specifically,the interfacial resistance is mainly generated from the adhesion of organic matrix and friction caused by nano-asperities on platelet surfaces.According to the interfacial resistance model,the stiction force originated from organic matrix adhesion is sensitive to its content,and the friction force produced by nano-asperities presents a positive correlation with their distribution density and dimension.Hence,the higher content of organic matrix of nacre with denser and larger nano-asperities on platelet surfaces in Nautilus shell contributes to a higher interfacial resistance.Therefore,it is the coupled effects of platelet geometries(i.e.aspect ratio and nano-asperity)and organic matrix that result in the high-strength and high-toughness nacreous structure in Nautilus shell,which is thus more conductive to inhabit in the deep sea with extremely high pressure.The present research findings are expected to provide beneficial references for the design of strong and tough nacre-inspired materials with appropriate platelet geometry and content of soft phase.展开更多
It is generally considered that heat treatments have a negative impact on the mechanical properties of nacre due to thermal decomposition of the organic matrix.However,the present work investigated the microindentatio...It is generally considered that heat treatments have a negative impact on the mechanical properties of nacre due to thermal decomposition of the organic matrix.However,the present work investigated the microindentation behavior on fresh and heat-treated nacres from two orthogonal directions,and the results demonstrate that both hardness value and damage tolerance can remain almost unchanged on the cross-section with the organic matrix degeneration,despite a significant deterioration on the platelet surface.Theoretical analyses suggest that the anisotropic response of indentation behavior to heat treatment in nacre is primarily caused by its structural orientation.Specifically,compared with a single layer of irregular interplatelet interfaces in cross-sectional specimens,the multiple layers of parallel interlamellar interfaces in in-plane specimens exhibit a much greater ability to impede indenter-triggered destruction,and heat treatments would reduce the in-plane hardness but nearly have no effect on the cross-sectional hardness.Moreover,the deeper embedding of platelets in cross-sectional specimens enhances their resistance to interface cracking caused by organic matrix degradation at high temperatures,leading to a reduced sensitivity to damage.Therefore,the indentation behavior of nacre shows different tendencies in response to variations in the organic matrix state along normal and parallel directions.展开更多
The microstructures ofAtrina pectinata and freshwater mussel shells are investigated by optical microscopy and scanning electron microscopy. The mechanical properties of these shells are characterized by nanoindentati...The microstructures ofAtrina pectinata and freshwater mussel shells are investigated by optical microscopy and scanning electron microscopy. The mechanical properties of these shells are characterized by nanoindentation and three-point bending tests. Results show that both shells possess a prismatic microstructure mainly composed of columnar crystals and an organic matrix. The fracture toughness of the prismatic structure of Atrina pectinata and freshwater mussel are approximately 1.15 MPa.m1/2 and 0.87 MPa.m1/2, respectively, while the fracture toughness of natural calcite is approximately 0.2 MPa.m1/2. Calculated results from indentations agree with those obtained from the three-point bending tests. The columnar crystal material shows excellent fracture toughness due to grain refinement. In addition, the organic matrix of the prismatic layer can arrest cracks, and thereby improves the fracture toughness.展开更多
An ion chromatography(IC) system coupled with on-line column-switching technique was used to determine anions ofμg/g levels in organic chemicals of analytical reagent grade.A novel polystyrene-divinylbenzene-carbon...An ion chromatography(IC) system coupled with on-line column-switching technique was used to determine anions ofμg/g levels in organic chemicals of analytical reagent grade.A novel polystyrene-divinylbenzene-carbon nanotube(PS-DVB-CNT) stationary phase was utilized for matrix elimination.A calibration study was conducted by preparing and analyzing eight concentrations(between 10 and 5000μg/L) of eight standards in deionized water.The linearity was between 0.9978 and 1.And the detection limits ranged from 1.54μg/L to 10.02μg/L.A spiking study was performed on two representative organic chemicals.The recoveries were between 84.3%and 119.6%.展开更多
Based on the transmission electron micrographs of nacre, the existence of mineral bridges in the organic matrix interface is confirmed. It is proposed that the microarchitecture of nacre should be considered as a “br...Based on the transmission electron micrographs of nacre, the existence of mineral bridges in the organic matrix interface is confirmed. It is proposed that the microarchitecture of nacre should be considered as a “brick-bridge-mortar” (BBM) arrangement rather than traditional “brick and mortar” (BM) one. Experiments and analyses indicate that the mineral bridges effectively affect the strength and toughness of the interfaces in nacre. Comparison with a laminated composite with BM structure, SiC/BN, shows that the pattern of the crack extension and the toughening mechanism of the two materials are different. This reveals that the mineral bridges play a key role in the toughening mechanisms of nacre, which gives a conceptual guidance in material synthesis.展开更多
Haze in China is primarily caused by high pollution of atmospheric fine particulates(PM2.5).However, the detailed source structures of PM2.5 light extinction have not been well established, especially for the roles ...Haze in China is primarily caused by high pollution of atmospheric fine particulates(PM2.5).However, the detailed source structures of PM2.5 light extinction have not been well established, especially for the roles of various organic aerosols, which makes haze management lack specified targets. This study obtained the mass concentrations of the chemical compositions and the light extinction coefficients of fine particles in the winter in Dongguan, Guangdong Province, using high time resolution aerosol observation instruments. We combined the positive matrix factor(PMF) analysis model of organic aerosols and the multiple linear regression method to establish a quantitative relationship model between the main chemical components, in particular the different sources of organic aerosols and the extinction coefficients of fine particles with a high goodness of fit(R^2= 0.953). The results show that the contribution rates of ammonium sulphate,ammonium nitrate, biomass burning organic aerosol(BBOA), secondary organic aerosol(SOA) and black carbon(BC) were 48.1%, 20.7%, 15.0%, 10.6%, and 5.6%, respectively. It can be seen that the contribution of the secondary aerosols is much higher than that of the primary aerosols(79.4% versus 20.6%) and are a major factor in the visibility decline. BBOA is found to have a high visibility destroying potential, with a high mass extinction coefficient, and was the largest contributor during some high pollution periods. A more detailed analysis indicates that the contribution of the enhanced absorption caused by BC mixing state was approximately 37.7% of the total particle absorption and should not be neglected.展开更多
Three-dimensional fluorescence excitation–emission matrix(EEM) coupled with parallel factor analysis(PARAFAC) was performed for a total of 18 water samples taken from three water sources(two lakes and one wastew...Three-dimensional fluorescence excitation–emission matrix(EEM) coupled with parallel factor analysis(PARAFAC) was performed for a total of 18 water samples taken from three water sources(two lakes and one wastewater treatment plant(WWTP) secondary effluent),with the purpose of identifying the major ultrafiltration(UF) membrane foulants in different water sources. Three fluorescent components(C1, C2 and C3) were identified,which represented terrestrially derived humic-like substances(C1), microbially derived humic-like substances(C2), and protein-like substances(C3). The correlations between the different fluorescent components and UF membrane fouling were analyzed. It was shown that for the WWTP secondary effluent, all three components(C1, C2 and C3) made a considerable contribution to the irreversible and total fouling of the UF membrane.However, for the two lakes, only the C3 exhibited a strong correlation with membrane fouling, indicating that the protein-like substances were the major membrane foulants in the lake waters. Significant attachment of C1, C2 and C3 to the UF membrane was also confirmed by mass balance analyses for the WWTP secondary effluent; while the attachment of C1 and C2 was shown to be negligible for the two lakes. The results may provide basic formation for developing suitable fouling control strategies for sustainable UF processes.展开更多
The swine effluent studied was collected from scale pig farms,located in Yujiang County of Jiangxi Province,China,and duckweed(Spriodela polyrrhiza) was selected to dispose the effluent.The purpose of this study was...The swine effluent studied was collected from scale pig farms,located in Yujiang County of Jiangxi Province,China,and duckweed(Spriodela polyrrhiza) was selected to dispose the effluent.The purpose of this study was to elucidate the effects of duckweed growth on the dissolved organic matter composition in swine effluent.Throughout the experiment period,the concentrations of organic matter were determined regularly,and the excitationemission matrix(3DEEM) spectroscopy was used to characterize the fluorescence component.Compared with no-duckweed treatments(controls),the specific ultra-violet absorbance at 254 nm(SUVA254) was increased by a final average of 34.4%as the phytoremediation using duckweed,and the removal rate of DOC was increased by a final average of 28.0%.In swine effluent,four fluorescence components were identified,including two protein-like(tryptophan,tyrosine) and two humic-like(fulvic acids,humic acids) components.For all treatments,the concentrations of protein-like components decreased by a final average of 69.0%.As the growth of duckweed,the concentrations of humic-like components were increased by a final average of 123.5%than controls.Significant and positive correlations were observed between SUVA254 and humic-like components.Compared with the controls,the humification index(HIX) increased by a final average of 9.0%for duckweed treatments.Meanwhile,the duckweed growth leaded to a lower biological index(BIX) and a higher proportion of microbial-derived fulvic acids than controls.In conclusion,the duckweed remediation not only enhanced the removal rate of organic matter in swine effluent,but also increased the percent of humic substances.展开更多
In order to understand the transport and humification processes of dissolved organic matter(DOM) within sediments of a semi-arid floodplain at Rifle,Colorado,fluorescence excitation–emission matrix(EEM) spectrosc...In order to understand the transport and humification processes of dissolved organic matter(DOM) within sediments of a semi-arid floodplain at Rifle,Colorado,fluorescence excitation–emission matrix(EEM) spectroscopy,humification index(HIX) and specific UV absorbance(SUVA) at 254 nm were applied for characterizing depth and seasonal variations of DOM composition.Results revealed that late spring snowmelt leached relatively fresh DOM from plant residue and soil organic matter down into the deeper vadose zone(VZ).More humified DOM is preferentially adsorbed by upper VZ sediments,while non-or lesshumified DOM was transported into the deeper VZ.Interestingly,DOM at all depths undergoes rapid biological humification process evidenced by the products of microbial by-product-like(i.e.,tyrosine-like and tryptophan-like) matter in late spring and early summer,particularly in the deeper VZ,resulting in more humified DOM(e.g.,fulvic-acid-like and humic-acid-like substances) at the end of year.This indicates that DOM transport is dominated by spring snowmelt,and DOM humification is controlled by microbial degradation,with seasonal variations.It is expected that these relatively simple spectroscopic measurements(e.g.,EEM spectroscopy,HIX and SUVA) applied to depth-and temporally-distributed pore-water samples can provide useful insights into transport and humification of DOM in other subsurface environments as well.展开更多
文摘This paper aims at demonstrating that an acceptable level of performance as a group facilitator can be achieved byhospitality industry managers in a 35-hour course, to a maximum of fourteen trainees, experienced in groupleadership but not in small-group facilitation or large-group coordination. Based on a six-step model fororganizational intervention, the course was run in co-facilitation, using the effect of demonstration, modelling, andobservation to improve performance at individual level. The course represents a mix of organizational behaviourand human resources management that has proved to be effective in preparing managers to improve organizationalinnovation and accelerate change in companies. Each step produced outputs, namely three innovation projects.Participants rated the course in every item of an extensive questionnaire as Good and Very Good, except theintroduction (pre-consult), which was considered “too theoretical”. Therefore, the course model proved to beadequate for the preparation of managers as coaches for organizational innovation in the hospitality industry. As tofuture developments, they will have to do mostly with the functioning of a matrix structure in the hospitality industry,so that the whole approach may have a full impact on the company.
基金Project supported by the Science and Technology Commission of Shanghai Municipality(Grant No.09530708600)the Shanghai AM Foundation(Grant No.09700714000)
文摘The paper puts forward a method on controlling the AM-OLED panel to display image with high gray scale levels. It also gives an ASIC design sample to implement this method. A twenty sub-fields scan scheme has been taken into use in the chip to display 256 gray scale levels on a QVGA resolution AM-OLED display screen. The functions of image scaling and rotating have also been implemented for multiply application. The simulation and chip test result show that the chip design has met the design requirements.
文摘The oxidative desulphurization process of coal with different metamorphism degrees treated by an air-steam mixture has been studied.It has been shown that the pyrite present in black coal and anthracite is oxidized with the sulphur dioxide formation,and the process chemical mechanism does not depend on the quality of organic matter.The medium-metamorphized coal,capable of turning into a plastic state and cake in the range of investigated temperatures(350~450 ℃),is desulphurized with the greatest difficulty.The chemical mechanism dealing with the transformations of pyritic sulphur present in brown coal differs from similar processes taking place in black coal and anthracite,because FeS2 is converted with hydrogen sulphide formation at desulphurization.
基金The project supported by the Natural Science Foundation of Chinese Academy of Sciences (KJ951-1-201) the National Natural Science Foundation of China (19891180 and 10072067)
文摘Nacre, or mother-of-pearl, is a kind of composites of aragonite platelets sandwiched between organic materials. Its excellent mechanical properties are thought to stem from the micro architecture that is traditionally described as a 'brick and mortar' arrangement. In this paper, a new microstructure, referred to as mineral bridge in the biomineralization, is directly observed in the organic matrix layers (mortar) of nacre. This is an indication that the organic matrix layer of nacre should be treated as a three-dimensional interface and the micro architecture of nacre ought to be considered as a 'brick-bridge-mortar' structure rather than the traditional one. Experiments and analyses show that the mineral bridges not only improve the mechanical properties of the organic matrix layers but also play an important role in the pattern of the crack extension in nacre.
基金financially supported by the National Natural Science Foundation of China(No.51902043)the China Postdoctoral Science Foundation(No.2018M641704)+1 种基金the Fundamental Research Funds for the Central Universities(No.N180203018)partially supported by the National Natural Science Foundation of China(Nos.51571058 and 51871048)。
文摘To explore the differences in mechanical behavior of nacre between shells that live in different water depths,the microstructures,phase composition and related mechanical properties of nacre under indentation,three-point bending and shear tests in deep-sea Nautilus and freshwater Cristaria plicata shells were systematically investigated.It is found that the nacreous structure in Nautilus shell exhibits an outstanding combination of high strength and high toughness compared with that in C.plicata shell,attributing to its larger aspect ratio of platelet and interfacial shear resistance.Specifically,the interfacial resistance is mainly generated from the adhesion of organic matrix and friction caused by nano-asperities on platelet surfaces.According to the interfacial resistance model,the stiction force originated from organic matrix adhesion is sensitive to its content,and the friction force produced by nano-asperities presents a positive correlation with their distribution density and dimension.Hence,the higher content of organic matrix of nacre with denser and larger nano-asperities on platelet surfaces in Nautilus shell contributes to a higher interfacial resistance.Therefore,it is the coupled effects of platelet geometries(i.e.aspect ratio and nano-asperity)and organic matrix that result in the high-strength and high-toughness nacreous structure in Nautilus shell,which is thus more conductive to inhabit in the deep sea with extremely high pressure.The present research findings are expected to provide beneficial references for the design of strong and tough nacre-inspired materials with appropriate platelet geometry and content of soft phase.
基金financially supported by the National Natural Science Foundation of China(Grant No.51902043)the Fundamental Research Funds for the Central Universities(Grant Nos.N2102002,N2102007 and N180203018)supported by the National Natural Science Foundation of China(No.52171108).
文摘It is generally considered that heat treatments have a negative impact on the mechanical properties of nacre due to thermal decomposition of the organic matrix.However,the present work investigated the microindentation behavior on fresh and heat-treated nacres from two orthogonal directions,and the results demonstrate that both hardness value and damage tolerance can remain almost unchanged on the cross-section with the organic matrix degeneration,despite a significant deterioration on the platelet surface.Theoretical analyses suggest that the anisotropic response of indentation behavior to heat treatment in nacre is primarily caused by its structural orientation.Specifically,compared with a single layer of irregular interplatelet interfaces in cross-sectional specimens,the multiple layers of parallel interlamellar interfaces in in-plane specimens exhibit a much greater ability to impede indenter-triggered destruction,and heat treatments would reduce the in-plane hardness but nearly have no effect on the cross-sectional hardness.Moreover,the deeper embedding of platelets in cross-sectional specimens enhances their resistance to interface cracking caused by organic matrix degradation at high temperatures,leading to a reduced sensitivity to damage.Therefore,the indentation behavior of nacre shows different tendencies in response to variations in the organic matrix state along normal and parallel directions.
基金This work is partly supported by the National Natural Science Foundation of China (No.51205012), Beijing Nova Program (No.Z141104001814035), and National Higher-education Institution General Research and Development Project. The authors would like to thank Dr. Zhaodong Li from Central Iron & Steel Re- search Institue of China for assistance on nanoindenta- tion testing.
文摘The microstructures ofAtrina pectinata and freshwater mussel shells are investigated by optical microscopy and scanning electron microscopy. The mechanical properties of these shells are characterized by nanoindentation and three-point bending tests. Results show that both shells possess a prismatic microstructure mainly composed of columnar crystals and an organic matrix. The fracture toughness of the prismatic structure of Atrina pectinata and freshwater mussel are approximately 1.15 MPa.m1/2 and 0.87 MPa.m1/2, respectively, while the fracture toughness of natural calcite is approximately 0.2 MPa.m1/2. Calculated results from indentations agree with those obtained from the three-point bending tests. The columnar crystal material shows excellent fracture toughness due to grain refinement. In addition, the organic matrix of the prismatic layer can arrest cracks, and thereby improves the fracture toughness.
基金supported by National Natural Science Foundation of China(Nos.20775070, J0830413)Zhejiang Provincial Natural Science Foundation of China(Nos.R4080124,Y4090104,Y4090078)Zhejiang Qianjiang Project of Science and Technology for Competent People(No.2008R10028)
文摘An ion chromatography(IC) system coupled with on-line column-switching technique was used to determine anions ofμg/g levels in organic chemicals of analytical reagent grade.A novel polystyrene-divinylbenzene-carbon nanotube(PS-DVB-CNT) stationary phase was utilized for matrix elimination.A calibration study was conducted by preparing and analyzing eight concentrations(between 10 and 5000μg/L) of eight standards in deionized water.The linearity was between 0.9978 and 1.And the detection limits ranged from 1.54μg/L to 10.02μg/L.A spiking study was performed on two representative organic chemicals.The recoveries were between 84.3%and 119.6%.
基金the National Natural Science Foundations of China (Grant Nos. 19891180 and 10072067) and the Natural Science Foundation of Chinese Academy of Sciences (KJ951-1-201) .
文摘Based on the transmission electron micrographs of nacre, the existence of mineral bridges in the organic matrix interface is confirmed. It is proposed that the microarchitecture of nacre should be considered as a “brick-bridge-mortar” (BBM) arrangement rather than traditional “brick and mortar” (BM) one. Experiments and analyses indicate that the mineral bridges effectively affect the strength and toughness of the interfaces in nacre. Comparison with a laminated composite with BM structure, SiC/BN, shows that the pattern of the crack extension and the toughening mechanism of the two materials are different. This reveals that the mineral bridges play a key role in the toughening mechanisms of nacre, which gives a conceptual guidance in material synthesis.
基金supported by the National Natural Science Foundation of China(Nos.41622304,U1301234)the Ministry of Science and Technology of China(Nos.2014BAC21B03,2016YFC0203600)the Science and Technology Plan of Shenzhen Municipality
文摘Haze in China is primarily caused by high pollution of atmospheric fine particulates(PM2.5).However, the detailed source structures of PM2.5 light extinction have not been well established, especially for the roles of various organic aerosols, which makes haze management lack specified targets. This study obtained the mass concentrations of the chemical compositions and the light extinction coefficients of fine particles in the winter in Dongguan, Guangdong Province, using high time resolution aerosol observation instruments. We combined the positive matrix factor(PMF) analysis model of organic aerosols and the multiple linear regression method to establish a quantitative relationship model between the main chemical components, in particular the different sources of organic aerosols and the extinction coefficients of fine particles with a high goodness of fit(R^2= 0.953). The results show that the contribution rates of ammonium sulphate,ammonium nitrate, biomass burning organic aerosol(BBOA), secondary organic aerosol(SOA) and black carbon(BC) were 48.1%, 20.7%, 15.0%, 10.6%, and 5.6%, respectively. It can be seen that the contribution of the secondary aerosols is much higher than that of the primary aerosols(79.4% versus 20.6%) and are a major factor in the visibility decline. BBOA is found to have a high visibility destroying potential, with a high mass extinction coefficient, and was the largest contributor during some high pollution periods. A more detailed analysis indicates that the contribution of the enhanced absorption caused by BC mixing state was approximately 37.7% of the total particle absorption and should not be neglected.
基金supported by the National Natural Science Foundation of China(No.51208140)the National Water Pollution Control and Treatment Science and Technology Major Project of China(No.2012ZX07201002)
文摘Three-dimensional fluorescence excitation–emission matrix(EEM) coupled with parallel factor analysis(PARAFAC) was performed for a total of 18 water samples taken from three water sources(two lakes and one wastewater treatment plant(WWTP) secondary effluent),with the purpose of identifying the major ultrafiltration(UF) membrane foulants in different water sources. Three fluorescent components(C1, C2 and C3) were identified,which represented terrestrially derived humic-like substances(C1), microbially derived humic-like substances(C2), and protein-like substances(C3). The correlations between the different fluorescent components and UF membrane fouling were analyzed. It was shown that for the WWTP secondary effluent, all three components(C1, C2 and C3) made a considerable contribution to the irreversible and total fouling of the UF membrane.However, for the two lakes, only the C3 exhibited a strong correlation with membrane fouling, indicating that the protein-like substances were the major membrane foulants in the lake waters. Significant attachment of C1, C2 and C3 to the UF membrane was also confirmed by mass balance analyses for the WWTP secondary effluent; while the attachment of C1 and C2 was shown to be negligible for the two lakes. The results may provide basic formation for developing suitable fouling control strategies for sustainable UF processes.
基金supported by the Special Fund for Agro-scientific Research in the Public Interest of China(No.201203050)the National Science Foundation of China(No.41171233)the Natural Science Foundation of Jiangsu Province,China(No.BK20131044)
文摘The swine effluent studied was collected from scale pig farms,located in Yujiang County of Jiangxi Province,China,and duckweed(Spriodela polyrrhiza) was selected to dispose the effluent.The purpose of this study was to elucidate the effects of duckweed growth on the dissolved organic matter composition in swine effluent.Throughout the experiment period,the concentrations of organic matter were determined regularly,and the excitationemission matrix(3DEEM) spectroscopy was used to characterize the fluorescence component.Compared with no-duckweed treatments(controls),the specific ultra-violet absorbance at 254 nm(SUVA254) was increased by a final average of 34.4%as the phytoremediation using duckweed,and the removal rate of DOC was increased by a final average of 28.0%.In swine effluent,four fluorescence components were identified,including two protein-like(tryptophan,tyrosine) and two humic-like(fulvic acids,humic acids) components.For all treatments,the concentrations of protein-like components decreased by a final average of 69.0%.As the growth of duckweed,the concentrations of humic-like components were increased by a final average of 123.5%than controls.Significant and positive correlations were observed between SUVA254 and humic-like components.Compared with the controls,the humification index(HIX) increased by a final average of 9.0%for duckweed treatments.Meanwhile,the duckweed growth leaded to a lower biological index(BIX) and a higher proportion of microbial-derived fulvic acids than controls.In conclusion,the duckweed remediation not only enhanced the removal rate of organic matter in swine effluent,but also increased the percent of humic substances.
基金partially performed at the Molecular Foundry,Lawrence Berkeley National Laboratorysupported as part of the Sustainable Systems Scientific Focus Area program at Lawrence Berkeley National Laboratorysupported by the U.S.Department of Energy,Office of Science,Office of Biological and Environmental Research,Subsurface Biogeochemical Research Program,through Contract No.DE-AC02-05CH11231 between Lawrence Berkeley National Laboratory and the U.S.Department of Energy
文摘In order to understand the transport and humification processes of dissolved organic matter(DOM) within sediments of a semi-arid floodplain at Rifle,Colorado,fluorescence excitation–emission matrix(EEM) spectroscopy,humification index(HIX) and specific UV absorbance(SUVA) at 254 nm were applied for characterizing depth and seasonal variations of DOM composition.Results revealed that late spring snowmelt leached relatively fresh DOM from plant residue and soil organic matter down into the deeper vadose zone(VZ).More humified DOM is preferentially adsorbed by upper VZ sediments,while non-or lesshumified DOM was transported into the deeper VZ.Interestingly,DOM at all depths undergoes rapid biological humification process evidenced by the products of microbial by-product-like(i.e.,tyrosine-like and tryptophan-like) matter in late spring and early summer,particularly in the deeper VZ,resulting in more humified DOM(e.g.,fulvic-acid-like and humic-acid-like substances) at the end of year.This indicates that DOM transport is dominated by spring snowmelt,and DOM humification is controlled by microbial degradation,with seasonal variations.It is expected that these relatively simple spectroscopic measurements(e.g.,EEM spectroscopy,HIX and SUVA) applied to depth-and temporally-distributed pore-water samples can provide useful insights into transport and humification of DOM in other subsurface environments as well.