The Experts below are selected from a list of 192 Experts worldwide ranked by ideXlab platform
L. E. Ekberg - One of the best experts on this subject based on the ideXlab platform.
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Characterization of indoor sources of fine and ultrafine particles: a study conducted in a full‐scale chamber
Indoor Air, 2005Co-Authors: Asghar Afshari, U. Matson, L. E. EkbergAbstract:Humans and their activities are known to generate considerable amounts of particulate matter indoors. Some of the activities are cooking, smoking and cleaning. In this study 13 different particle sources were for the first time examined in a 32 m3 full-scale chamber with an air change rate of 1.7 ± 0.1/h. Two different instruments, a condensation particle counter (CPC) and an optical particle counter (OPC) were used to quantitatively determine ultrafine and fine particle emissions, respectively. The CPC measures particles from 0.02 μm to larger than 1.0 μm. The OPC was adjusted to measure particle concentrations in eight fractions between 0.3 and 1.0 μm. The sources were cigarette side-stream smoke, pure wax candles, scented candles, a vacuum cleaner, an air-freshener spray, a Flat Iron (with and without steam) on a cotton sheet, electric radiators, an electric stove, a gas stove, and frying meat. The cigarette burning, frying meat, air freshener spray and gas stove showed a particle size distribution that changed over time towards larger particles. In most of the experiments the maximum concentration was reached within a few minutes. Typically, the increase of the particle concentration immediately after activation of the source was more rapid than the decay of the concentration observed after deactivation of the source. The highest observed concentration of ultrafine particles was approximately 241,000 particles/cm 3 and originated from the combustion of pure wax candles. The weakest generation of ultrafine particles (1.17 × 107 particles per second) was observed when Ironing without steam on a cotton sheet, which resulted in a concentration of 550 particles/cm3 in the chamber air. The highest generation rate (1.47 × 1010 particles per second) was observed in the radiator test.
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Characterization of indoor sources of fine and ultrafine particles: A study conducted in a full-scale chamber
Indoor Air, 2005Co-Authors: Asghar Afshari, U. Matson, L. E. EkbergAbstract:UNLABELLED: Humans and their activities are known to generate considerable amounts of particulate matter indoors. Some of the activities are cooking, smoking and cleaning. In this study 13 different particle sources were for the first time examined in a 32 m3 full-scale chamber with an air change rate of 1.7 +/- 0.1/h. Two different instruments, a condensation particle counter (CPC) and an optical particle counter (OPC) were used to quantitatively determine ultrafine and fine particle emissions, respectively. The CPC measures particles from 0.02 microm to larger than 1.0 microm. The OPC was adjusted to measure particle concentrations in eight fractions between 0.3 and 1.0 microm. The sources were cigarette side-stream smoke, pure wax candles, scented candles, a vacuum cleaner, an air-freshener spray, a Flat Iron (with and without steam) on a cotton sheet, electric radiators, an electric stove, a gas stove, and frying meat. The cigarette burning, frying meat, air freshener spray and gas stove showed a particle size distribution that changed over time towards larger particles. In most of the experiments the maximum concentration was reached within a few minutes. Typically, the increase of the particle concentration immediately after activation of the source was more rapid than the decay of the concentration observed after deactivation of the source. The highest observed concentration of ultrafine particles was approximately 241,000 particles/cm3 and originated from the combustion of pure wax candles. The weakest generation of ultrafine particles (1.17 x 10(7) particles per second) was observed when Ironing without steam on a cotton sheet, which resulted in a concentration of 550 particles/cm3 in the chamber air. The highest generation rate (1.47 x 10(10) particles per second) was observed in the radiator test. PRACTICAL IMPLICATIONS: Humans and their activities are known to generate substantial amounts of particulate matter indoors and potentially they can have a strong influence on short-term exposure. In this study a quantitative determination of the emissions of fine and ultrafine particles from different indoor sources was performed. The aim is a better understanding of the origin and fate of indoor particles. The results may be useful for Indoor Air Quality models.
Jens Ulrich - One of the best experts on this subject based on the ideXlab platform.
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A ~565 Ma old glaciation in the Ediacaran of peri-Gondwanan West Africa
International Journal of Earth Sciences, 2018Co-Authors: Ulf Linnemann, Agustín Pieren Pidal, Mandy Hofmann, Kerstin Drost, Cecilio Quesada, Axel Gerdes, Linda Marko, Andreas Gärtner, Johannes Zieger, Jens UlrichAbstract:In the Cadomian orogen of the NE Bohemian Massif and of SW Iberia, a post-Gaskiers glacial event dated at c. 565 Ma has been detected. Such Ediacaran-aged glaciomarine deposits occur in the Weesenstein and Clanzschwitz groups of the Saxo-Thuringian zone (Bohemia) and in the Lower Alcudian group of the southern Central Iberian zone (Iberia). Both areas are parts of Cadomia situated in the Western and Central European Variscides. Glaciomarine sedimentary rocks are characterized by such features as dropstones, Flat Iron-shaped pebbles (“ Bügeleisen - Geschiebe ”), facetted pebbles, dreikanters, and zircon grains affected by ice abrasion. For age and provenance determination, LA–ICP–MS U–Pb ages ( n = 1124) and Hf isotope ( n = 446) analyses were performed. The maximum age of the glaciomarine deposits within a Cadomian back-arc basin based on U–Pb analytics resulted in the youngest detrital zircon populations showing ages of 562–565 Ma and of c. 566–576 Ma old zircon derived from granitoid pebbles within the diamictites. The youngest age recorded was 538–540 Ma based on zircon from the plutons which had intruded the previously deformed Ediacaran metasedimentary rocks. Previously described glaciomarine diamictites of Cadomia (Weesenstein, Clanzschwitz, and Orellana diamictites) are most definitely younger than the c. 579–581 Ma Gaskiers glaciation in Newfoundland (Gaskiers) and in SE New England (Squantum). We propose the term Weesenstein – Orellana glaciation for this new Ediacaran glacial event, named after the most relevant regions of exposure. Palaeogeographically, these glaciomarine diamictites and related sedimentary deposits lie on the periphery of the West African Craton (western peri-Gondwana), and evidence has been provided by detrital zircon U–Pb ages and their Hf isotope composition. Correlation with similar glaciomarine deposits in the Anti-Atlas (Bou Azzer) and Saudi Arabia suggests a continued distribution of post-Gaskiers glacial deposits along the Gondwana margin of Northern Africa. The Weesenstein – Orellana glaciation correlates in part with the Shuram–Wonoka δ^13C anomaly.
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A ~565 Ma old glaciation in the Ediacaran of peri-Gondwanan West Africa
International Journal of Earth Sciences, 2017Co-Authors: Ulf Linnemann, Agustín Pieren Pidal, Mandy Hofmann, Kerstin Drost, Cecilio Quesada, Axel Gerdes, Linda Marko, Andreas Gärtner, Johannes Zieger, Jens UlrichAbstract:In the Cadomian orogen of the NE Bohemian Massif and of SW Iberia, a post-Gaskiers glacial event dated at c. 565 Ma has been detected. Such Ediacaran-aged glaciomarine deposits occur in the Weesenstein and Clanzschwitz groups of the Saxo-Thuringian zone (Bohemia) and in the Lower Alcudian group of the southern Central Iberian zone (Iberia). Both areas are parts of Cadomia situated in the Western and Central European Variscides. Glaciomarine sedimentary rocks are characterized by such features as dropstones, Flat Iron-shaped pebbles (“Bugeleisen-Geschiebe”), facetted pebbles, dreikanters, and zircon grains affected by ice abrasion. For age and provenance determination, LA–ICP–MS U–Pb ages (n = 1124) and Hf isotope (n = 446) analyses were performed. The maximum age of the glaciomarine deposits within a Cadomian back-arc basin based on U–Pb analytics resulted in the youngest detrital zircon populations showing ages of 562–565 Ma and of c. 566–576 Ma old zircon derived from granitoid pebbles within the diamictites. The youngest age recorded was 538–540 Ma based on zircon from the plutons which had intruded the previously deformed Ediacaran metasedimentary rocks. Previously described glaciomarine diamictites of Cadomia (Weesenstein, Clanzschwitz, and Orellana diamictites) are most definitely younger than the c. 579–581 Ma Gaskiers glaciation in Newfoundland (Gaskiers) and in SE New England (Squantum). We propose the term Weesenstein–Orellana glaciation for this new Ediacaran glacial event, named after the most relevant regions of exposure. Palaeogeographically, these glaciomarine diamictites and related sedimentary deposits lie on the periphery of the West African Craton (western peri-Gondwana), and evidence has been provided by detrital zircon U–Pb ages and their Hf isotope composition. Correlation with similar glaciomarine deposits in the Anti-Atlas (Bou Azzer) and Saudi Arabia suggests a continued distribution of post-Gaskiers glacial deposits along the Gondwana margin of Northern Africa. The Weesenstein–Orellana glaciation correlates in part with the Shuram–Wonoka δ13C anomaly.
Asghar Afshari - One of the best experts on this subject based on the ideXlab platform.
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Characterization of indoor sources of fine and ultrafine particles: a study conducted in a full‐scale chamber
Indoor Air, 2005Co-Authors: Asghar Afshari, U. Matson, L. E. EkbergAbstract:Humans and their activities are known to generate considerable amounts of particulate matter indoors. Some of the activities are cooking, smoking and cleaning. In this study 13 different particle sources were for the first time examined in a 32 m3 full-scale chamber with an air change rate of 1.7 ± 0.1/h. Two different instruments, a condensation particle counter (CPC) and an optical particle counter (OPC) were used to quantitatively determine ultrafine and fine particle emissions, respectively. The CPC measures particles from 0.02 μm to larger than 1.0 μm. The OPC was adjusted to measure particle concentrations in eight fractions between 0.3 and 1.0 μm. The sources were cigarette side-stream smoke, pure wax candles, scented candles, a vacuum cleaner, an air-freshener spray, a Flat Iron (with and without steam) on a cotton sheet, electric radiators, an electric stove, a gas stove, and frying meat. The cigarette burning, frying meat, air freshener spray and gas stove showed a particle size distribution that changed over time towards larger particles. In most of the experiments the maximum concentration was reached within a few minutes. Typically, the increase of the particle concentration immediately after activation of the source was more rapid than the decay of the concentration observed after deactivation of the source. The highest observed concentration of ultrafine particles was approximately 241,000 particles/cm 3 and originated from the combustion of pure wax candles. The weakest generation of ultrafine particles (1.17 × 107 particles per second) was observed when Ironing without steam on a cotton sheet, which resulted in a concentration of 550 particles/cm3 in the chamber air. The highest generation rate (1.47 × 1010 particles per second) was observed in the radiator test.
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Characterization of indoor sources of fine and ultrafine particles: A study conducted in a full-scale chamber
Indoor Air, 2005Co-Authors: Asghar Afshari, U. Matson, L. E. EkbergAbstract:UNLABELLED: Humans and their activities are known to generate considerable amounts of particulate matter indoors. Some of the activities are cooking, smoking and cleaning. In this study 13 different particle sources were for the first time examined in a 32 m3 full-scale chamber with an air change rate of 1.7 +/- 0.1/h. Two different instruments, a condensation particle counter (CPC) and an optical particle counter (OPC) were used to quantitatively determine ultrafine and fine particle emissions, respectively. The CPC measures particles from 0.02 microm to larger than 1.0 microm. The OPC was adjusted to measure particle concentrations in eight fractions between 0.3 and 1.0 microm. The sources were cigarette side-stream smoke, pure wax candles, scented candles, a vacuum cleaner, an air-freshener spray, a Flat Iron (with and without steam) on a cotton sheet, electric radiators, an electric stove, a gas stove, and frying meat. The cigarette burning, frying meat, air freshener spray and gas stove showed a particle size distribution that changed over time towards larger particles. In most of the experiments the maximum concentration was reached within a few minutes. Typically, the increase of the particle concentration immediately after activation of the source was more rapid than the decay of the concentration observed after deactivation of the source. The highest observed concentration of ultrafine particles was approximately 241,000 particles/cm3 and originated from the combustion of pure wax candles. The weakest generation of ultrafine particles (1.17 x 10(7) particles per second) was observed when Ironing without steam on a cotton sheet, which resulted in a concentration of 550 particles/cm3 in the chamber air. The highest generation rate (1.47 x 10(10) particles per second) was observed in the radiator test. PRACTICAL IMPLICATIONS: Humans and their activities are known to generate substantial amounts of particulate matter indoors and potentially they can have a strong influence on short-term exposure. In this study a quantitative determination of the emissions of fine and ultrafine particles from different indoor sources was performed. The aim is a better understanding of the origin and fate of indoor particles. The results may be useful for Indoor Air Quality models.
Ulf Linnemann - One of the best experts on this subject based on the ideXlab platform.
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A ~565 Ma old glaciation in the Ediacaran of peri-Gondwanan West Africa
International Journal of Earth Sciences, 2018Co-Authors: Ulf Linnemann, Agustín Pieren Pidal, Mandy Hofmann, Kerstin Drost, Cecilio Quesada, Axel Gerdes, Linda Marko, Andreas Gärtner, Johannes Zieger, Jens UlrichAbstract:In the Cadomian orogen of the NE Bohemian Massif and of SW Iberia, a post-Gaskiers glacial event dated at c. 565 Ma has been detected. Such Ediacaran-aged glaciomarine deposits occur in the Weesenstein and Clanzschwitz groups of the Saxo-Thuringian zone (Bohemia) and in the Lower Alcudian group of the southern Central Iberian zone (Iberia). Both areas are parts of Cadomia situated in the Western and Central European Variscides. Glaciomarine sedimentary rocks are characterized by such features as dropstones, Flat Iron-shaped pebbles (“ Bügeleisen - Geschiebe ”), facetted pebbles, dreikanters, and zircon grains affected by ice abrasion. For age and provenance determination, LA–ICP–MS U–Pb ages ( n = 1124) and Hf isotope ( n = 446) analyses were performed. The maximum age of the glaciomarine deposits within a Cadomian back-arc basin based on U–Pb analytics resulted in the youngest detrital zircon populations showing ages of 562–565 Ma and of c. 566–576 Ma old zircon derived from granitoid pebbles within the diamictites. The youngest age recorded was 538–540 Ma based on zircon from the plutons which had intruded the previously deformed Ediacaran metasedimentary rocks. Previously described glaciomarine diamictites of Cadomia (Weesenstein, Clanzschwitz, and Orellana diamictites) are most definitely younger than the c. 579–581 Ma Gaskiers glaciation in Newfoundland (Gaskiers) and in SE New England (Squantum). We propose the term Weesenstein – Orellana glaciation for this new Ediacaran glacial event, named after the most relevant regions of exposure. Palaeogeographically, these glaciomarine diamictites and related sedimentary deposits lie on the periphery of the West African Craton (western peri-Gondwana), and evidence has been provided by detrital zircon U–Pb ages and their Hf isotope composition. Correlation with similar glaciomarine deposits in the Anti-Atlas (Bou Azzer) and Saudi Arabia suggests a continued distribution of post-Gaskiers glacial deposits along the Gondwana margin of Northern Africa. The Weesenstein – Orellana glaciation correlates in part with the Shuram–Wonoka δ^13C anomaly.
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A ~565 Ma old glaciation in the Ediacaran of peri-Gondwanan West Africa
International Journal of Earth Sciences, 2017Co-Authors: Ulf Linnemann, Agustín Pieren Pidal, Mandy Hofmann, Kerstin Drost, Cecilio Quesada, Axel Gerdes, Linda Marko, Andreas Gärtner, Johannes Zieger, Jens UlrichAbstract:In the Cadomian orogen of the NE Bohemian Massif and of SW Iberia, a post-Gaskiers glacial event dated at c. 565 Ma has been detected. Such Ediacaran-aged glaciomarine deposits occur in the Weesenstein and Clanzschwitz groups of the Saxo-Thuringian zone (Bohemia) and in the Lower Alcudian group of the southern Central Iberian zone (Iberia). Both areas are parts of Cadomia situated in the Western and Central European Variscides. Glaciomarine sedimentary rocks are characterized by such features as dropstones, Flat Iron-shaped pebbles (“Bugeleisen-Geschiebe”), facetted pebbles, dreikanters, and zircon grains affected by ice abrasion. For age and provenance determination, LA–ICP–MS U–Pb ages (n = 1124) and Hf isotope (n = 446) analyses were performed. The maximum age of the glaciomarine deposits within a Cadomian back-arc basin based on U–Pb analytics resulted in the youngest detrital zircon populations showing ages of 562–565 Ma and of c. 566–576 Ma old zircon derived from granitoid pebbles within the diamictites. The youngest age recorded was 538–540 Ma based on zircon from the plutons which had intruded the previously deformed Ediacaran metasedimentary rocks. Previously described glaciomarine diamictites of Cadomia (Weesenstein, Clanzschwitz, and Orellana diamictites) are most definitely younger than the c. 579–581 Ma Gaskiers glaciation in Newfoundland (Gaskiers) and in SE New England (Squantum). We propose the term Weesenstein–Orellana glaciation for this new Ediacaran glacial event, named after the most relevant regions of exposure. Palaeogeographically, these glaciomarine diamictites and related sedimentary deposits lie on the periphery of the West African Craton (western peri-Gondwana), and evidence has been provided by detrital zircon U–Pb ages and their Hf isotope composition. Correlation with similar glaciomarine deposits in the Anti-Atlas (Bou Azzer) and Saudi Arabia suggests a continued distribution of post-Gaskiers glacial deposits along the Gondwana margin of Northern Africa. The Weesenstein–Orellana glaciation correlates in part with the Shuram–Wonoka δ13C anomaly.
U. Matson - One of the best experts on this subject based on the ideXlab platform.
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Characterization of indoor sources of fine and ultrafine particles: a study conducted in a full‐scale chamber
Indoor Air, 2005Co-Authors: Asghar Afshari, U. Matson, L. E. EkbergAbstract:Humans and their activities are known to generate considerable amounts of particulate matter indoors. Some of the activities are cooking, smoking and cleaning. In this study 13 different particle sources were for the first time examined in a 32 m3 full-scale chamber with an air change rate of 1.7 ± 0.1/h. Two different instruments, a condensation particle counter (CPC) and an optical particle counter (OPC) were used to quantitatively determine ultrafine and fine particle emissions, respectively. The CPC measures particles from 0.02 μm to larger than 1.0 μm. The OPC was adjusted to measure particle concentrations in eight fractions between 0.3 and 1.0 μm. The sources were cigarette side-stream smoke, pure wax candles, scented candles, a vacuum cleaner, an air-freshener spray, a Flat Iron (with and without steam) on a cotton sheet, electric radiators, an electric stove, a gas stove, and frying meat. The cigarette burning, frying meat, air freshener spray and gas stove showed a particle size distribution that changed over time towards larger particles. In most of the experiments the maximum concentration was reached within a few minutes. Typically, the increase of the particle concentration immediately after activation of the source was more rapid than the decay of the concentration observed after deactivation of the source. The highest observed concentration of ultrafine particles was approximately 241,000 particles/cm 3 and originated from the combustion of pure wax candles. The weakest generation of ultrafine particles (1.17 × 107 particles per second) was observed when Ironing without steam on a cotton sheet, which resulted in a concentration of 550 particles/cm3 in the chamber air. The highest generation rate (1.47 × 1010 particles per second) was observed in the radiator test.
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Characterization of indoor sources of fine and ultrafine particles: A study conducted in a full-scale chamber
Indoor Air, 2005Co-Authors: Asghar Afshari, U. Matson, L. E. EkbergAbstract:UNLABELLED: Humans and their activities are known to generate considerable amounts of particulate matter indoors. Some of the activities are cooking, smoking and cleaning. In this study 13 different particle sources were for the first time examined in a 32 m3 full-scale chamber with an air change rate of 1.7 +/- 0.1/h. Two different instruments, a condensation particle counter (CPC) and an optical particle counter (OPC) were used to quantitatively determine ultrafine and fine particle emissions, respectively. The CPC measures particles from 0.02 microm to larger than 1.0 microm. The OPC was adjusted to measure particle concentrations in eight fractions between 0.3 and 1.0 microm. The sources were cigarette side-stream smoke, pure wax candles, scented candles, a vacuum cleaner, an air-freshener spray, a Flat Iron (with and without steam) on a cotton sheet, electric radiators, an electric stove, a gas stove, and frying meat. The cigarette burning, frying meat, air freshener spray and gas stove showed a particle size distribution that changed over time towards larger particles. In most of the experiments the maximum concentration was reached within a few minutes. Typically, the increase of the particle concentration immediately after activation of the source was more rapid than the decay of the concentration observed after deactivation of the source. The highest observed concentration of ultrafine particles was approximately 241,000 particles/cm3 and originated from the combustion of pure wax candles. The weakest generation of ultrafine particles (1.17 x 10(7) particles per second) was observed when Ironing without steam on a cotton sheet, which resulted in a concentration of 550 particles/cm3 in the chamber air. The highest generation rate (1.47 x 10(10) particles per second) was observed in the radiator test. PRACTICAL IMPLICATIONS: Humans and their activities are known to generate substantial amounts of particulate matter indoors and potentially they can have a strong influence on short-term exposure. In this study a quantitative determination of the emissions of fine and ultrafine particles from different indoor sources was performed. The aim is a better understanding of the origin and fate of indoor particles. The results may be useful for Indoor Air Quality models.