The Experts below are selected from a list of 276 Experts worldwide ranked by ideXlab platform
Stephan Weinbruch - One of the best experts on this subject based on the ideXlab platform.
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Bulk Composition of northern African dust and its source sediments — A compilation
Earth-Science Reviews, 2013Co-Authors: Dirk Scheuvens, Lothar Schütz, Konrad Kandler, Martin Ebert, Stephan WeinbruchAbstract:Abstract This paper presents a review of Bulk Compositional data of northern African dust and its potential source sediments and includes elemental, isotope and mineralogical data. Northern African dust represents about one half of the total global atmospheric mineral dust burden, and its uplift, transport and deposition have strong impacts on climate and various terrestrial and marine ecosystems. The chemical data set shows, that an ‘average northern African dust’ exhibits comparable Si, Fe and Mn contents with respect to the average Composition of the upper continental crust, is slightly depleted in the alkali metals K and Na, and enriched in Ti and P. However, the complete data set yields clear evidence that northern African dust and its source sediments are Compositionally heterogeneous on a regional scale and that this heterogeneity can be used to differentiate between major potential source areas on the basis of so-called source markers. An evaluation of these Compositional fingerprints shows that the following parameters and especially their combination are effective in the discrimination of the most active source areas in northern Africa: ratio of (Ca + Mg)/Fe [wt.%], calcite (or carbonate) content, palygorskite occurrence and abundance, illite/kaolinite ratio, ƐNd(0) value, and 87Sr/86Sr ratio. For example, the data set corroborates previous ideas, which assign carbonate-, illite- and palygorskite-rich mineral dusts to north(west)ern source regions. Because most of the above listed source markers do not change substantially during transport, even far-traveled dusts may be assigned to specific potential source areas in northern Africa. Some limitations of the presented data set are also discussed. Our compilation reveals some substantial gaps in the knowledge of the Composition of source sediments and mineral dusts from important potential source areas that should be filled in the future. The here compiled data set can be used as a reference frame, when incorporating the Composition of source sediments (e.g., mineralogy) into global or regional dust transport models and can be compared with source analysis by remote sensing or back-trajectory analysis. However, source apportionment studies supported by our data set will not only be useful for actual dust samples, but will also be helpful for the understanding of paleo-wind directions and hence paleo-climatological conditions through the investigation of Quaternary eolian sediments deposited in and around northern Africa.
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Bulk Composition of northern african dust and its source sediments a compilation
Earth-Science Reviews, 2013Co-Authors: Dirk Scheuvens, Lothar Schütz, Konrad Kandler, Martin Ebert, Stephan WeinbruchAbstract:Abstract This paper presents a review of Bulk Compositional data of northern African dust and its potential source sediments and includes elemental, isotope and mineralogical data. Northern African dust represents about one half of the total global atmospheric mineral dust burden, and its uplift, transport and deposition have strong impacts on climate and various terrestrial and marine ecosystems. The chemical data set shows, that an ‘average northern African dust’ exhibits comparable Si, Fe and Mn contents with respect to the average Composition of the upper continental crust, is slightly depleted in the alkali metals K and Na, and enriched in Ti and P. However, the complete data set yields clear evidence that northern African dust and its source sediments are Compositionally heterogeneous on a regional scale and that this heterogeneity can be used to differentiate between major potential source areas on the basis of so-called source markers. An evaluation of these Compositional fingerprints shows that the following parameters and especially their combination are effective in the discrimination of the most active source areas in northern Africa: ratio of (Ca + Mg)/Fe [wt.%], calcite (or carbonate) content, palygorskite occurrence and abundance, illite/kaolinite ratio, ƐNd(0) value, and 87Sr/86Sr ratio. For example, the data set corroborates previous ideas, which assign carbonate-, illite- and palygorskite-rich mineral dusts to north(west)ern source regions. Because most of the above listed source markers do not change substantially during transport, even far-traveled dusts may be assigned to specific potential source areas in northern Africa. Some limitations of the presented data set are also discussed. Our compilation reveals some substantial gaps in the knowledge of the Composition of source sediments and mineral dusts from important potential source areas that should be filled in the future. The here compiled data set can be used as a reference frame, when incorporating the Composition of source sediments (e.g., mineralogy) into global or regional dust transport models and can be compared with source analysis by remote sensing or back-trajectory analysis. However, source apportionment studies supported by our data set will not only be useful for actual dust samples, but will also be helpful for the understanding of paleo-wind directions and hence paleo-climatological conditions through the investigation of Quaternary eolian sediments deposited in and around northern Africa.
Dirk Scheuvens - One of the best experts on this subject based on the ideXlab platform.
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Bulk Composition of northern African dust and its source sediments — A compilation
Earth-Science Reviews, 2013Co-Authors: Dirk Scheuvens, Lothar Schütz, Konrad Kandler, Martin Ebert, Stephan WeinbruchAbstract:Abstract This paper presents a review of Bulk Compositional data of northern African dust and its potential source sediments and includes elemental, isotope and mineralogical data. Northern African dust represents about one half of the total global atmospheric mineral dust burden, and its uplift, transport and deposition have strong impacts on climate and various terrestrial and marine ecosystems. The chemical data set shows, that an ‘average northern African dust’ exhibits comparable Si, Fe and Mn contents with respect to the average Composition of the upper continental crust, is slightly depleted in the alkali metals K and Na, and enriched in Ti and P. However, the complete data set yields clear evidence that northern African dust and its source sediments are Compositionally heterogeneous on a regional scale and that this heterogeneity can be used to differentiate between major potential source areas on the basis of so-called source markers. An evaluation of these Compositional fingerprints shows that the following parameters and especially their combination are effective in the discrimination of the most active source areas in northern Africa: ratio of (Ca + Mg)/Fe [wt.%], calcite (or carbonate) content, palygorskite occurrence and abundance, illite/kaolinite ratio, ƐNd(0) value, and 87Sr/86Sr ratio. For example, the data set corroborates previous ideas, which assign carbonate-, illite- and palygorskite-rich mineral dusts to north(west)ern source regions. Because most of the above listed source markers do not change substantially during transport, even far-traveled dusts may be assigned to specific potential source areas in northern Africa. Some limitations of the presented data set are also discussed. Our compilation reveals some substantial gaps in the knowledge of the Composition of source sediments and mineral dusts from important potential source areas that should be filled in the future. The here compiled data set can be used as a reference frame, when incorporating the Composition of source sediments (e.g., mineralogy) into global or regional dust transport models and can be compared with source analysis by remote sensing or back-trajectory analysis. However, source apportionment studies supported by our data set will not only be useful for actual dust samples, but will also be helpful for the understanding of paleo-wind directions and hence paleo-climatological conditions through the investigation of Quaternary eolian sediments deposited in and around northern Africa.
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Bulk Composition of northern african dust and its source sediments a compilation
Earth-Science Reviews, 2013Co-Authors: Dirk Scheuvens, Lothar Schütz, Konrad Kandler, Martin Ebert, Stephan WeinbruchAbstract:Abstract This paper presents a review of Bulk Compositional data of northern African dust and its potential source sediments and includes elemental, isotope and mineralogical data. Northern African dust represents about one half of the total global atmospheric mineral dust burden, and its uplift, transport and deposition have strong impacts on climate and various terrestrial and marine ecosystems. The chemical data set shows, that an ‘average northern African dust’ exhibits comparable Si, Fe and Mn contents with respect to the average Composition of the upper continental crust, is slightly depleted in the alkali metals K and Na, and enriched in Ti and P. However, the complete data set yields clear evidence that northern African dust and its source sediments are Compositionally heterogeneous on a regional scale and that this heterogeneity can be used to differentiate between major potential source areas on the basis of so-called source markers. An evaluation of these Compositional fingerprints shows that the following parameters and especially their combination are effective in the discrimination of the most active source areas in northern Africa: ratio of (Ca + Mg)/Fe [wt.%], calcite (or carbonate) content, palygorskite occurrence and abundance, illite/kaolinite ratio, ƐNd(0) value, and 87Sr/86Sr ratio. For example, the data set corroborates previous ideas, which assign carbonate-, illite- and palygorskite-rich mineral dusts to north(west)ern source regions. Because most of the above listed source markers do not change substantially during transport, even far-traveled dusts may be assigned to specific potential source areas in northern Africa. Some limitations of the presented data set are also discussed. Our compilation reveals some substantial gaps in the knowledge of the Composition of source sediments and mineral dusts from important potential source areas that should be filled in the future. The here compiled data set can be used as a reference frame, when incorporating the Composition of source sediments (e.g., mineralogy) into global or regional dust transport models and can be compared with source analysis by remote sensing or back-trajectory analysis. However, source apportionment studies supported by our data set will not only be useful for actual dust samples, but will also be helpful for the understanding of paleo-wind directions and hence paleo-climatological conditions through the investigation of Quaternary eolian sediments deposited in and around northern Africa.
Konrad Kandler - One of the best experts on this subject based on the ideXlab platform.
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Bulk Composition of northern African dust and its source sediments — A compilation
Earth-Science Reviews, 2013Co-Authors: Dirk Scheuvens, Lothar Schütz, Konrad Kandler, Martin Ebert, Stephan WeinbruchAbstract:Abstract This paper presents a review of Bulk Compositional data of northern African dust and its potential source sediments and includes elemental, isotope and mineralogical data. Northern African dust represents about one half of the total global atmospheric mineral dust burden, and its uplift, transport and deposition have strong impacts on climate and various terrestrial and marine ecosystems. The chemical data set shows, that an ‘average northern African dust’ exhibits comparable Si, Fe and Mn contents with respect to the average Composition of the upper continental crust, is slightly depleted in the alkali metals K and Na, and enriched in Ti and P. However, the complete data set yields clear evidence that northern African dust and its source sediments are Compositionally heterogeneous on a regional scale and that this heterogeneity can be used to differentiate between major potential source areas on the basis of so-called source markers. An evaluation of these Compositional fingerprints shows that the following parameters and especially their combination are effective in the discrimination of the most active source areas in northern Africa: ratio of (Ca + Mg)/Fe [wt.%], calcite (or carbonate) content, palygorskite occurrence and abundance, illite/kaolinite ratio, ƐNd(0) value, and 87Sr/86Sr ratio. For example, the data set corroborates previous ideas, which assign carbonate-, illite- and palygorskite-rich mineral dusts to north(west)ern source regions. Because most of the above listed source markers do not change substantially during transport, even far-traveled dusts may be assigned to specific potential source areas in northern Africa. Some limitations of the presented data set are also discussed. Our compilation reveals some substantial gaps in the knowledge of the Composition of source sediments and mineral dusts from important potential source areas that should be filled in the future. The here compiled data set can be used as a reference frame, when incorporating the Composition of source sediments (e.g., mineralogy) into global or regional dust transport models and can be compared with source analysis by remote sensing or back-trajectory analysis. However, source apportionment studies supported by our data set will not only be useful for actual dust samples, but will also be helpful for the understanding of paleo-wind directions and hence paleo-climatological conditions through the investigation of Quaternary eolian sediments deposited in and around northern Africa.
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Bulk Composition of northern african dust and its source sediments a compilation
Earth-Science Reviews, 2013Co-Authors: Dirk Scheuvens, Lothar Schütz, Konrad Kandler, Martin Ebert, Stephan WeinbruchAbstract:Abstract This paper presents a review of Bulk Compositional data of northern African dust and its potential source sediments and includes elemental, isotope and mineralogical data. Northern African dust represents about one half of the total global atmospheric mineral dust burden, and its uplift, transport and deposition have strong impacts on climate and various terrestrial and marine ecosystems. The chemical data set shows, that an ‘average northern African dust’ exhibits comparable Si, Fe and Mn contents with respect to the average Composition of the upper continental crust, is slightly depleted in the alkali metals K and Na, and enriched in Ti and P. However, the complete data set yields clear evidence that northern African dust and its source sediments are Compositionally heterogeneous on a regional scale and that this heterogeneity can be used to differentiate between major potential source areas on the basis of so-called source markers. An evaluation of these Compositional fingerprints shows that the following parameters and especially their combination are effective in the discrimination of the most active source areas in northern Africa: ratio of (Ca + Mg)/Fe [wt.%], calcite (or carbonate) content, palygorskite occurrence and abundance, illite/kaolinite ratio, ƐNd(0) value, and 87Sr/86Sr ratio. For example, the data set corroborates previous ideas, which assign carbonate-, illite- and palygorskite-rich mineral dusts to north(west)ern source regions. Because most of the above listed source markers do not change substantially during transport, even far-traveled dusts may be assigned to specific potential source areas in northern Africa. Some limitations of the presented data set are also discussed. Our compilation reveals some substantial gaps in the knowledge of the Composition of source sediments and mineral dusts from important potential source areas that should be filled in the future. The here compiled data set can be used as a reference frame, when incorporating the Composition of source sediments (e.g., mineralogy) into global or regional dust transport models and can be compared with source analysis by remote sensing or back-trajectory analysis. However, source apportionment studies supported by our data set will not only be useful for actual dust samples, but will also be helpful for the understanding of paleo-wind directions and hence paleo-climatological conditions through the investigation of Quaternary eolian sediments deposited in and around northern Africa.
A Czerwinski - One of the best experts on this subject based on the ideXlab platform.
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effect of temperature electrode potential and Bulk Composition on hydrogen electrosorption into palladium ruthenium alloys comparative study with other binary systems
Electrocatalysis, 2018Co-Authors: K Hubkowska, M łukaszewski, A CzerwinskiAbstract:The influence of temperature between 283 K and 328 K on hydrogen electrosorption into Pd-Ru alloys in the Bulk Composition range 87–100% at. Pd was studied voltammetrically and chronoamperometrically in 0.5 M H2SO4 solution. The maximum alloy ability to absorb hydrogen decreases with increasing temperature. The extent of hydrogen absorption/desorption hysteresis is slightly reduced with increasing temperature and markedly reduced with increasing Ru Bulk content. Both increasing temperature and Ru Bulk content results not only in a decrease in the thermodynamic stability of the hydride phase but also in an improvement in the kinetics of hydrogen electrosorption. Pd-Ru alloys containing more than ca. 97% at. Pd absorb more hydrogen than pure Pd, while further Ru additive results in a significant deterioration of the alloy ability to absorb hydrogen. The data on the influence of temperature and alloy Bulk Composition on the processes of hydrogen electrosorption in Pd binary alloys with Ru, Rh, Pt, and Au have been compared.
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Comparative study on the influence of temperature, electrode potential and alloy Bulk Composition on hydrogen electrosorption into Pd–Pt and Pd–Au alloys
Journal of Electroanalytical Chemistry, 2011Co-Authors: Mariusz Łukaszewski, K Hubkowska, A CzerwinskiAbstract:Abstract Hydrogen electrosorption into Pd-rich (>70% at. Pd in the Bulk) Pd–Pt and Pd–Au alloys has been studied in acidic solutions (0.5 M H2SO4) using cyclic voltammetry and chronoamperometry. The influence of temperature (in the range between 283 and 328 K), electrode potential and alloy Bulk Composition on hydrogen electrosorption properties is presented. It has been found that with increasing temperature the maximum amount of absorbed hydrogen decreases and the potential of absorbed hydrogen oxidation peak and the potential of the α–β phase transition are shifted negatively. Pd alloying with Pt or Au results in lower potential of absorbed hydrogen oxidation peak and lower maximum amount of absorbed hydrogen. The region of the α–β phase transition for Pd–Pt alloys is placed at lower potentials as compared to pure Pd indicating lower thermodynamic stability of the β-phase. In the case of Pd–Au alloys the phase transition region is placed at higher potentials indicating higher thermodynamic stability of the β-phase. The values of time needed for electrode saturation with hydrogen and its removal decrease with increasing temperature and increasing Bulk content of the alloying metals. The results have confirmed earlier suggestions that in the presence of both α- and β-phases of absorbed hydrogen the slow process of the phase transition controls the rate of the overall electrosorption process in thin Pd-based electrodes. The amounts of electrosorbed hydrogen for α- and β-phase boundaries, i.e. αmax and βmin, have been determined from the integration of the initial parts of current–time responses in hydrogen absorption and desorption processes.
Lothar Schütz - One of the best experts on this subject based on the ideXlab platform.
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Bulk Composition of northern African dust and its source sediments — A compilation
Earth-Science Reviews, 2013Co-Authors: Dirk Scheuvens, Lothar Schütz, Konrad Kandler, Martin Ebert, Stephan WeinbruchAbstract:Abstract This paper presents a review of Bulk Compositional data of northern African dust and its potential source sediments and includes elemental, isotope and mineralogical data. Northern African dust represents about one half of the total global atmospheric mineral dust burden, and its uplift, transport and deposition have strong impacts on climate and various terrestrial and marine ecosystems. The chemical data set shows, that an ‘average northern African dust’ exhibits comparable Si, Fe and Mn contents with respect to the average Composition of the upper continental crust, is slightly depleted in the alkali metals K and Na, and enriched in Ti and P. However, the complete data set yields clear evidence that northern African dust and its source sediments are Compositionally heterogeneous on a regional scale and that this heterogeneity can be used to differentiate between major potential source areas on the basis of so-called source markers. An evaluation of these Compositional fingerprints shows that the following parameters and especially their combination are effective in the discrimination of the most active source areas in northern Africa: ratio of (Ca + Mg)/Fe [wt.%], calcite (or carbonate) content, palygorskite occurrence and abundance, illite/kaolinite ratio, ƐNd(0) value, and 87Sr/86Sr ratio. For example, the data set corroborates previous ideas, which assign carbonate-, illite- and palygorskite-rich mineral dusts to north(west)ern source regions. Because most of the above listed source markers do not change substantially during transport, even far-traveled dusts may be assigned to specific potential source areas in northern Africa. Some limitations of the presented data set are also discussed. Our compilation reveals some substantial gaps in the knowledge of the Composition of source sediments and mineral dusts from important potential source areas that should be filled in the future. The here compiled data set can be used as a reference frame, when incorporating the Composition of source sediments (e.g., mineralogy) into global or regional dust transport models and can be compared with source analysis by remote sensing or back-trajectory analysis. However, source apportionment studies supported by our data set will not only be useful for actual dust samples, but will also be helpful for the understanding of paleo-wind directions and hence paleo-climatological conditions through the investigation of Quaternary eolian sediments deposited in and around northern Africa.
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Bulk Composition of northern african dust and its source sediments a compilation
Earth-Science Reviews, 2013Co-Authors: Dirk Scheuvens, Lothar Schütz, Konrad Kandler, Martin Ebert, Stephan WeinbruchAbstract:Abstract This paper presents a review of Bulk Compositional data of northern African dust and its potential source sediments and includes elemental, isotope and mineralogical data. Northern African dust represents about one half of the total global atmospheric mineral dust burden, and its uplift, transport and deposition have strong impacts on climate and various terrestrial and marine ecosystems. The chemical data set shows, that an ‘average northern African dust’ exhibits comparable Si, Fe and Mn contents with respect to the average Composition of the upper continental crust, is slightly depleted in the alkali metals K and Na, and enriched in Ti and P. However, the complete data set yields clear evidence that northern African dust and its source sediments are Compositionally heterogeneous on a regional scale and that this heterogeneity can be used to differentiate between major potential source areas on the basis of so-called source markers. An evaluation of these Compositional fingerprints shows that the following parameters and especially their combination are effective in the discrimination of the most active source areas in northern Africa: ratio of (Ca + Mg)/Fe [wt.%], calcite (or carbonate) content, palygorskite occurrence and abundance, illite/kaolinite ratio, ƐNd(0) value, and 87Sr/86Sr ratio. For example, the data set corroborates previous ideas, which assign carbonate-, illite- and palygorskite-rich mineral dusts to north(west)ern source regions. Because most of the above listed source markers do not change substantially during transport, even far-traveled dusts may be assigned to specific potential source areas in northern Africa. Some limitations of the presented data set are also discussed. Our compilation reveals some substantial gaps in the knowledge of the Composition of source sediments and mineral dusts from important potential source areas that should be filled in the future. The here compiled data set can be used as a reference frame, when incorporating the Composition of source sediments (e.g., mineralogy) into global or regional dust transport models and can be compared with source analysis by remote sensing or back-trajectory analysis. However, source apportionment studies supported by our data set will not only be useful for actual dust samples, but will also be helpful for the understanding of paleo-wind directions and hence paleo-climatological conditions through the investigation of Quaternary eolian sediments deposited in and around northern Africa.
