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  1. Article ; Online: Effect of the polydispersity on the dispersion of polymers through silicas having different morphologies (fully porous and core-shell particles and monoliths).

    Nguyen, Khac-Long / Wernert, Véronique / Denoyel, Renaud

    Journal of chromatography. A

    2021  Volume 1641, Page(s) 461985

    Abstract: The effect of the polydispersity of polystyrenes on the dispersion through silicas having different morphologies (fully porous, core-shell particles and monoliths) was investigated. The heights equivalent to a theoretical plate (HETP) of those columns ... ...

    Abstract The effect of the polydispersity of polystyrenes on the dispersion through silicas having different morphologies (fully porous, core-shell particles and monoliths) was investigated. The heights equivalent to a theoretical plate (HETP) of those columns were measured for a small molecule (toluene) and a series of polystyrenes of different sizes in non-adsorbing conditions. The different contributions to the total HETP including polydispersity were determined experimentally. The longitudinal diffusion and the mass transfer resistance term were obtained from peak parking experiments. The eddy dispersion was obtained from models and experiments. The effect of polydispersity on the HETP values (H
    MeSH term(s) Calibration ; Chromatography, Liquid ; Diffusion ; Molecular Weight ; Particle Size ; Polymers/chemistry ; Polystyrenes/chemistry ; Porosity ; Silicon Dioxide/chemistry
    Chemical Substances Polymers ; Polystyrenes ; Silicon Dioxide (7631-86-9)
    Language English
    Publishing date 2021-02-09
    Publishing country Netherlands
    Document type Journal Article
    ZDB-ID 1171488-8
    ISSN 1873-3778 ; 0021-9673
    ISSN (online) 1873-3778
    ISSN 0021-9673
    DOI 10.1016/j.chroma.2021.461985
    Database MEDical Literature Analysis and Retrieval System OnLINE

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    In stock of ZB MED Cologne/Königswinter

    Zs.A 813: Show issues Location:
    Je nach Verfügbarkeit (siehe Angabe bei Bestand)
    bis Jg. 1994: Bestellungen von Artikeln über das Online-Bestellformular
    Jg. 1995 - 2021: Lesesall (1.OG)
    ab Jg. 2022: Lesesaal (EG)

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  2. Article: Impact of surface diffusion on transport through porous materials

    Wernert, Véronique / Nguyen, Khac Long / Levitz, Pierre / Coasne, Benoit / Denoyel, Renaud

    Journal of chromatography. 2022 Feb. 22, v. 1665

    2022  

    Abstract: The peak parking method was applied to evaluate the surface diffusivity Dₛ of polystyrenes dissolved in a THF/heptane mixture and transported through porous silica materials with various morphologies. With this method, the overall effective diffusivity D ...

    Abstract The peak parking method was applied to evaluate the surface diffusivity Dₛ of polystyrenes dissolved in a THF/heptane mixture and transported through porous silica materials with various morphologies. With this method, the overall effective diffusivity D is measured experimentally with coarse-grained models like Maxwell equation allowing one to infer the particle diffusivity Dₚz. Such particle diffusivity has two main contributions: in-pore diffusivity Dₚ and surface diffusivity Dₛ. The diffusion within the pores is determined experimentally using either non-adsorbing conditions or calculated from particle porosity, particle tortuosity, and hydrodynamic hindrance. The surface diffusion coefficient Dₛ is usually determined using models considering parallel diffusion in the pores and at the surface but this assumption is rather crude. In this paper, to address this problem, another approach is proposed using the Brownian motion of molecules in the pore space. These two approaches lead to similar equations relating the effective diffusion coefficient D, the in-pore diffusion Dₚ and surface diffusion Dₛ. The surface diffusion is analyzed as a function of the surface affinity of the probes considered here (polystyrenes of different molecular weights/lengths). Such surface affinity depends both on the probe chain length and surface chemistry of the host solid (the latter being characterized here through the silanol surface density). For short chain lengths, a non-monotonic change in the surface diffusion with affinity (i.e. retention factor) is observed in some cases. Yet, generally, as expected, surface diffusion decreases upon increasing the surface affinity. In contrast to short chain lengths, the longest chain lengths are less sensitive to the silanol surface density.
    Keywords chromatography ; diffusivity ; equations ; heptane ; hydrodynamics ; porosity ; silica
    Language English
    Dates of publication 2022-0222
    Publishing place Elsevier B.V.
    Document type Article
    ZDB-ID 218139-3
    ISSN 0021-9673 ; 0378-4355 ; 0376-737X
    ISSN 0021-9673 ; 0378-4355 ; 0376-737X
    DOI 10.1016/j.chroma.2022.462823
    Database NAL-Catalogue (AGRICOLA)

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    In stock of ZB MED Cologne/Königswinter

    Zs.A 813: Show issues Location:
    Je nach Verfügbarkeit (siehe Angabe bei Bestand)
    bis Jg. 1994: Bestellungen von Artikeln über das Online-Bestellformular
    Jg. 1995 - 2021: Lesesall (1.OG)
    ab Jg. 2022: Lesesaal (EG)

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  3. Article ; Online: Impact of surface diffusion on transport through porous materials.

    Wernert, Véronique / Nguyen, Khac Long / Levitz, Pierre / Coasne, Benoit / Denoyel, Renaud

    Journal of chromatography. A

    2022  Volume 1665, Page(s) 462823

    Abstract: The peak parking method was applied to evaluate the surface diffusivity ... ...

    Abstract The peak parking method was applied to evaluate the surface diffusivity D
    Language English
    Publishing date 2022-01-11
    Publishing country Netherlands
    Document type Journal Article
    ZDB-ID 1171488-8
    ISSN 1873-3778 ; 0021-9673
    ISSN (online) 1873-3778
    ISSN 0021-9673
    DOI 10.1016/j.chroma.2022.462823
    Database MEDical Literature Analysis and Retrieval System OnLINE

    Full text online

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    Kategorien

    In stock of ZB MED Cologne/Königswinter

    Zs.A 813: Show issues Location:
    Je nach Verfügbarkeit (siehe Angabe bei Bestand)
    bis Jg. 1994: Bestellungen von Artikeln über das Online-Bestellformular
    Jg. 1995 - 2021: Lesesall (1.OG)
    ab Jg. 2022: Lesesaal (EG)

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  4. Article: Engineering Perspectives and Environmental Life Cycle Optimization to Enhance Aggregate Mining in Vietnam

    Schneider, Petra / Bimesmeier, Tamara / Meyer, Andreas / Nguyen Khac, Long / Oswald, Klaus-Dieter / Pham Thi, Viet Anh / Riedel, Wolfgang / Schiller, Georg

    Sustainability. 2018 Feb. 15, v. 10, no. 2

    2018  

    Abstract: Cleaner Production (CP) addresses precautionary, site-specific environmental measures to reduce emissions and assess resource efficiency potentials at the point of origin by analyzing operational material and energy flows. The approach is generally based ...

    Abstract Cleaner Production (CP) addresses precautionary, site-specific environmental measures to reduce emissions and assess resource efficiency potentials at the point of origin by analyzing operational material and energy flows. The approach is generally based on the criteria quality as well as environmental/occupational health and safety, and promotes their integration. The paper presents options for applying CP to aggregate mining, based on a Life Cycle Assessment (LCA) and illustrated by results from a study of small-scale industrial aggregate mining in Hoa Binh Province (Vietnam). The regulatory framework to limit the impact of mining on the environment is largely comparable to international standards and is suitably enforced. Despite gaining experience through the practical handling of enforcement procedures over the long term, there is still a considerable potential to optimize CP strategies in Vietnam’s aggregate mining industry. This is shown by the results of a survey of aggregates mining companies in Hoa Binh Province as well as on-site data collection to determine the technological characteristics of production facilities alongside economic and environmental factors. The assessment of the survey is supported by LCA results for: (a) the existing situation; and (b) the scenario of a merging of companies, undertaken to improve the resource efficiency of the aggregate mining in Hoa Binh. Findings can help implement an integrated approach to foster the sustainable mining of building aggregates.
    Keywords business enterprises ; data collection ; emissions ; energy flow ; engineering ; environmental factors ; life cycle assessment ; mining ; occupational health and safety ; surveys ; Vietnam
    Language English
    Dates of publication 2018-0215
    Publishing place Multidisciplinary Digital Publishing Institute
    Document type Article
    ZDB-ID 2518383-7
    ISSN 2071-1050
    ISSN 2071-1050
    DOI 10.3390/su10020525
    Database NAL-Catalogue (AGRICOLA)

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  5. Article ; Online: Determination of the Emission Factors from Burning Common Domestic Cooking Fuels in Vietnam and its Application for Calculation of their Pollution Load

    Pham Ngoc Ho / Tran Hong Con / Dong Kim Loan / Duong Ngoc Bach / Pham Thi Viet Anh / Luong Thi Mai Ly / Pham Thi Thu Ha / Nguyen Khac Long

    EnvironmentAsia, Vol 6, Iss 1, Pp 45-

    2013  Volume 50

    Abstract: The emission factors and the air pollution load of domestic cooking processes in Vietnam were investigated. All the measurement results were given from experiments implemented at equipment imitated common cooking ways of almost households in different ... ...

    Abstract The emission factors and the air pollution load of domestic cooking processes in Vietnam were investigated. All the measurement results were given from experiments implemented at equipment imitated common cooking ways of almost households in different areas of Vietnam. The commonly used fuels concerning to the investigation were fuel gas, kerosene, comb coal, fossil coal, firewood, straw and rice stubble. The main parameters emitted from fuel burning processes such as SO2, NOx, CO, TSP and PM10 and related parameters such as temperature, pressure, exhaust gas flow rate were measured by the suitable equipment. Based on the measurement data, emission factors and pollution load were calculated and compared with other data published in the world.
    Keywords cooking fuel ; emission factor ; pollution load ; Geography. Anthropology. Recreation ; G ; Environmental sciences ; GE1-350
    Language English
    Publishing date 2013-01-01T00:00:00Z
    Publisher Thai Society of Higher Eduction Institutes on Environment
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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