The Experts below are selected from a list of 324 Experts worldwide ranked by ideXlab platform
Johan Uddling - One of the best experts on this subject based on the ideXlab platform.
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Effects of ground Surface Permeability on the growth of urban linden trees
Urban Ecosystems, 2018Co-Authors: Emilia Sand, Alessandro W Howe, Yvonne Andersson-sköld, Filip Moldan, Janina Konarska, Håkan Pleijel, Johan UddlingAbstract:Street trees are an important part of urban vegetation due to their provisioning of different types of ecosystem services such as local climate regulation and contribution to aesthetical and recreational values. In order to provide these services, urban trees need to endure many stress factors not present in natural environments, such as the widespread use of impervious Surfaces in the vicinity of street trees. However, few studies have evaluated the effect of this potential stress factor on urban tree growth. The aim of this study was therefore to investigate how ground Surface Permeability affects stem and current-year shoot growth of linden ( Tilia europaea ) street trees in Gothenburg, Sweden. We found that a small fraction of permeable ground Surface in the vertically projected tree crown area caused lower stem growth and strongly suppressed current-year shoot growth. This finding can guide future city planning, demonstrating that the vitality of street trees is compromised when the permeable Surface area in the vicinity of the tree is small.
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Effects of ground Surface Permeability on the growth of urban linden trees
Urban Ecosystems, 2018Co-Authors: Emilia Sand, Alessandro W Howe, Yvonne Andersson-sköld, Filip Moldan, Janina Konarska, Håkan Pleijel, Johan UddlingAbstract:Street trees are an important part of urban vegetation due to their provisioning of different types of ecosystem services such as local climate regulation and contribution to aesthetical and recrea ...
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Transpiration of urban trees and its cooling effect in a high latitude city
International Journal of Biometeorology, 2016Co-Authors: Janina Konarska, Björn Holmer, Martina Lutz, Fredrik Lindberg, Håkan Pleijel, Johan Uddling, Sofia ThorssonAbstract:An important ecosystem service provided by urban trees is the cooling effect caused by their transpiration. The aim of this study was to quantify the magnitude of daytime and night-time transpiration of common urban tree species in a high latitude city (Gothenburg, Sweden), to analyse the influence of weather conditions and Surface Permeability on the tree transpiration, and to find out whether tree transpiration contributed to daytime or nocturnal cooling. Stomatal conductance and leaf transpiration at day and night were measured on mature street and park trees of seven common tree species in Gothenburg: Tilia europaea , Quercus robur , Betula pendula , Acer platanoides , Aesculus hippocastanum , Fagus sylvatica and Prunus serrulata . Transpiration increased with vapour pressure deficit and photosynthetically active radiation. Midday rates of sunlit leaves ranged from less than 1 mmol m^−2 s^−1 ( B. pendula ) to over 3 mmol m^−2 s^−1 ( Q. robur ). Daytime stomatal conductance was positively related to the fraction of permeable Surfaces within the vertically projected crown area. A simple estimate of available rainwater, comprising of precipitation sum and fractional Surface Permeability within the crown area, was found to explain 68 % of variation in midday stomatal conductance. Night-time transpiration was observed in all studied species and amounted to 7 and 20 % of midday transpiration of sunlit and shaded leaves, respectively. With an estimated night-time latent heat flux of 24 W m^−2, tree transpiration significantly increased the cooling rate around and shortly after sunset, but not later in the night. Despite a strong midday latent heat flux of 206 W m^−2, a cooling effect of tree transpiration was not observed during the day.
Janina Konarska - One of the best experts on this subject based on the ideXlab platform.
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Effects of ground Surface Permeability on the growth of urban linden trees
Urban Ecosystems, 2018Co-Authors: Emilia Sand, Alessandro W Howe, Yvonne Andersson-sköld, Filip Moldan, Janina Konarska, Håkan Pleijel, Johan UddlingAbstract:Street trees are an important part of urban vegetation due to their provisioning of different types of ecosystem services such as local climate regulation and contribution to aesthetical and recreational values. In order to provide these services, urban trees need to endure many stress factors not present in natural environments, such as the widespread use of impervious Surfaces in the vicinity of street trees. However, few studies have evaluated the effect of this potential stress factor on urban tree growth. The aim of this study was therefore to investigate how ground Surface Permeability affects stem and current-year shoot growth of linden ( Tilia europaea ) street trees in Gothenburg, Sweden. We found that a small fraction of permeable ground Surface in the vertically projected tree crown area caused lower stem growth and strongly suppressed current-year shoot growth. This finding can guide future city planning, demonstrating that the vitality of street trees is compromised when the permeable Surface area in the vicinity of the tree is small.
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Effects of ground Surface Permeability on the growth of urban linden trees
Urban Ecosystems, 2018Co-Authors: Emilia Sand, Alessandro W Howe, Yvonne Andersson-sköld, Filip Moldan, Janina Konarska, Håkan Pleijel, Johan UddlingAbstract:Street trees are an important part of urban vegetation due to their provisioning of different types of ecosystem services such as local climate regulation and contribution to aesthetical and recrea ...
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Transpiration of urban trees and its cooling effect in a high latitude city
International Journal of Biometeorology, 2016Co-Authors: Janina Konarska, Björn Holmer, Martina Lutz, Fredrik Lindberg, Håkan Pleijel, Johan Uddling, Sofia ThorssonAbstract:An important ecosystem service provided by urban trees is the cooling effect caused by their transpiration. The aim of this study was to quantify the magnitude of daytime and night-time transpiration of common urban tree species in a high latitude city (Gothenburg, Sweden), to analyse the influence of weather conditions and Surface Permeability on the tree transpiration, and to find out whether tree transpiration contributed to daytime or nocturnal cooling. Stomatal conductance and leaf transpiration at day and night were measured on mature street and park trees of seven common tree species in Gothenburg: Tilia europaea , Quercus robur , Betula pendula , Acer platanoides , Aesculus hippocastanum , Fagus sylvatica and Prunus serrulata . Transpiration increased with vapour pressure deficit and photosynthetically active radiation. Midday rates of sunlit leaves ranged from less than 1 mmol m^−2 s^−1 ( B. pendula ) to over 3 mmol m^−2 s^−1 ( Q. robur ). Daytime stomatal conductance was positively related to the fraction of permeable Surfaces within the vertically projected crown area. A simple estimate of available rainwater, comprising of precipitation sum and fractional Surface Permeability within the crown area, was found to explain 68 % of variation in midday stomatal conductance. Night-time transpiration was observed in all studied species and amounted to 7 and 20 % of midday transpiration of sunlit and shaded leaves, respectively. With an estimated night-time latent heat flux of 24 W m^−2, tree transpiration significantly increased the cooling rate around and shortly after sunset, but not later in the night. Despite a strong midday latent heat flux of 206 W m^−2, a cooling effect of tree transpiration was not observed during the day.
Jörg Kärger - One of the best experts on this subject based on the ideXlab platform.
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Surface Permeability on zeolite NaCaA enhanced by layer deposition
Microporous and Mesoporous Materials, 2011Co-Authors: Tomas Binder, Ziad Adem, C. Krause, Margarita Krutyeva, Aisheng Huang, Jürgen Caro, Jörg KärgerAbstract:Abstract By PFG NMR diffusion measurements with short-chain length alkanes, the deposition of nano-sized LTA zeolite seed crystals on LTA single crystals and their secondary growth to Surface layers is shown to reduce rather than to enhance transport resistances at the crystal Surface. This, at first glance contra-intuitive, finding may be rationalised if the transport resistance on the external Surface of the nanoporous crystals of the as-synthesized material results from an essentially impenetrable layer with highly dispersed structural defects rather than from a quasi-continuous layer with extremely low guest diffusivity and/or solubility: if accompanied with an – even very small – enhancement of the defect density, irrespective of the increasing layer thickness a subsequent Surface treatment will enhance the Surface Permeability.
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Correlating Surface Permeability with intracrystalline diffusivity in nanoporous solids.
Physical review letters, 2011Co-Authors: Lars Heinke, Jörg KärgerAbstract:The rates of uptake and release of guest molecules in nanoporous solids are often strongly influenced or even controlled by transport resistances at the external Surface (‘‘Surface barriers’’) rather than by intraparticle diffusion, which was assumed to be rate controlling in many of the earlier kinetic studies. By correlating the Surface resistance with the intracrystalline diffusivity, we develop here a microkinetic model which closely reproduces the experimentally observed results for short-chain alkanes in Zn(tbip), a member of the novel metal-organic framework family of nanoporous materials. It seems likely that this mechanism, which is shown to provide a rational explanation of the commonly observed discrepancies between ‘‘macro’’ and ‘‘micro’’ measurements of intracrystalline diffusion, may be fairly general.
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Assessing Molecular Transport Properties of Nanoporous Materials by Interference Microscopy: Remarkable Effects of Composition and Microstructure on Diffusion in the Silicoaluminophosphate Zeotype STA-7
Journal of the American Chemical Society, 2010Co-Authors: Despina Tzoulaki, Lars Heinke, Paul A. Wright, María A. Castro, Pablo Cubillas, Michael W. Anderson, Wuzong Zhou, Jörg KärgerAbstract:The influence of the chemical composition and of the storage and activation protocol on the diffusion of methanol into strongly chemically zoned crystals of the silicoaluminophosphate zeotype STA-7 has been investigated by interference microscopy. Analysis of the evolution of transient intracrystalline concentration profiles reveals that just-calcined SAPO STA-7 crystals with lower Si content (Si/(Si + P) = 0.18) exhibit higher Surface Permeability and bulk diffusivity than those with higher Si content (S/(Si + P) = 0.37). Remarkably, crystals with the higher Si content which were stored in the calcined form crack during activation along planes of weakness already present in the as-prepared crystals, creating fresh Surfaces through regions of lower Si that are much more easily penetrated by the adsorbing methanol than are the original Surfaces.
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Three-dimensional diffusion in nanoporous host-guest materials monitored by interference microscopy
EPL (Europhysics Letters), 2007Co-Authors: Lars Heinke, Pavel Kortunov, Despina Tzoulaki, Maria Castro, Paul A. Wright, Jörg KärgerAbstract:For the first time, by the application of interference microscopy, direct monitoring of three-dimensional guest diffusion in nanoporous host-guest systems has become possible. The primary experimental evidence accessible using this technique is the integral over the concentration in the direction of observation. In the present letter, an algorithm is presented which provides direct access to the local concentrations. For the system under study, methanol in the silicoaluminophosphate zeotype SAPO STA-7, the intracrystalline concentration evolving during a sorption experiment is calculated by the suggested method and the resulting data is used to determine the concentration dependence of the principal values of the diffusion tensor as well as of the Surface Permeability.
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Surface barriers on nanoporous particles: A new method of their quantitation by PFG NMR
Microporous and Mesoporous Materials, 2007Co-Authors: Margarita Krutyeva, X. Yang, Sergey Vasenkov, Juergen Caro, Jörg KärgerAbstract:The Surface Permeability of zeolite crystals of type NaCaA for small alkane molecules (methane and ethane) was estimated by using a novel method, analysing NMR tracer desorption measurements. It is based on the measurement of both the relative amount of tracer exchange and the corresponding effective coefficients of intracrystalline diffusion and their correlation with the results of model calculations by dynamic Monte Carlo simulations. For the two LTA specimens investigated, already in the as-synthesized zeolite crystals notable Surface resistances have been observed. Surface permeabilities have been studied in dependence on temperature, sorbate and crystal size.
Emilia Sand - One of the best experts on this subject based on the ideXlab platform.
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Effects of ground Surface Permeability on the growth of urban linden trees
Urban Ecosystems, 2018Co-Authors: Emilia Sand, Alessandro W Howe, Yvonne Andersson-sköld, Filip Moldan, Janina Konarska, Håkan Pleijel, Johan UddlingAbstract:Street trees are an important part of urban vegetation due to their provisioning of different types of ecosystem services such as local climate regulation and contribution to aesthetical and recreational values. In order to provide these services, urban trees need to endure many stress factors not present in natural environments, such as the widespread use of impervious Surfaces in the vicinity of street trees. However, few studies have evaluated the effect of this potential stress factor on urban tree growth. The aim of this study was therefore to investigate how ground Surface Permeability affects stem and current-year shoot growth of linden ( Tilia europaea ) street trees in Gothenburg, Sweden. We found that a small fraction of permeable ground Surface in the vertically projected tree crown area caused lower stem growth and strongly suppressed current-year shoot growth. This finding can guide future city planning, demonstrating that the vitality of street trees is compromised when the permeable Surface area in the vicinity of the tree is small.
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Effects of ground Surface Permeability on the growth of urban linden trees
Urban Ecosystems, 2018Co-Authors: Emilia Sand, Alessandro W Howe, Yvonne Andersson-sköld, Filip Moldan, Janina Konarska, Håkan Pleijel, Johan UddlingAbstract:Street trees are an important part of urban vegetation due to their provisioning of different types of ecosystem services such as local climate regulation and contribution to aesthetical and recrea ...
Håkan Pleijel - One of the best experts on this subject based on the ideXlab platform.
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Effects of ground Surface Permeability on the growth of urban linden trees
Urban Ecosystems, 2018Co-Authors: Emilia Sand, Alessandro W Howe, Yvonne Andersson-sköld, Filip Moldan, Janina Konarska, Håkan Pleijel, Johan UddlingAbstract:Street trees are an important part of urban vegetation due to their provisioning of different types of ecosystem services such as local climate regulation and contribution to aesthetical and recreational values. In order to provide these services, urban trees need to endure many stress factors not present in natural environments, such as the widespread use of impervious Surfaces in the vicinity of street trees. However, few studies have evaluated the effect of this potential stress factor on urban tree growth. The aim of this study was therefore to investigate how ground Surface Permeability affects stem and current-year shoot growth of linden ( Tilia europaea ) street trees in Gothenburg, Sweden. We found that a small fraction of permeable ground Surface in the vertically projected tree crown area caused lower stem growth and strongly suppressed current-year shoot growth. This finding can guide future city planning, demonstrating that the vitality of street trees is compromised when the permeable Surface area in the vicinity of the tree is small.
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Effects of ground Surface Permeability on the growth of urban linden trees
Urban Ecosystems, 2018Co-Authors: Emilia Sand, Alessandro W Howe, Yvonne Andersson-sköld, Filip Moldan, Janina Konarska, Håkan Pleijel, Johan UddlingAbstract:Street trees are an important part of urban vegetation due to their provisioning of different types of ecosystem services such as local climate regulation and contribution to aesthetical and recrea ...
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Transpiration of urban trees and its cooling effect in a high latitude city
International Journal of Biometeorology, 2016Co-Authors: Janina Konarska, Björn Holmer, Martina Lutz, Fredrik Lindberg, Håkan Pleijel, Johan Uddling, Sofia ThorssonAbstract:An important ecosystem service provided by urban trees is the cooling effect caused by their transpiration. The aim of this study was to quantify the magnitude of daytime and night-time transpiration of common urban tree species in a high latitude city (Gothenburg, Sweden), to analyse the influence of weather conditions and Surface Permeability on the tree transpiration, and to find out whether tree transpiration contributed to daytime or nocturnal cooling. Stomatal conductance and leaf transpiration at day and night were measured on mature street and park trees of seven common tree species in Gothenburg: Tilia europaea , Quercus robur , Betula pendula , Acer platanoides , Aesculus hippocastanum , Fagus sylvatica and Prunus serrulata . Transpiration increased with vapour pressure deficit and photosynthetically active radiation. Midday rates of sunlit leaves ranged from less than 1 mmol m^−2 s^−1 ( B. pendula ) to over 3 mmol m^−2 s^−1 ( Q. robur ). Daytime stomatal conductance was positively related to the fraction of permeable Surfaces within the vertically projected crown area. A simple estimate of available rainwater, comprising of precipitation sum and fractional Surface Permeability within the crown area, was found to explain 68 % of variation in midday stomatal conductance. Night-time transpiration was observed in all studied species and amounted to 7 and 20 % of midday transpiration of sunlit and shaded leaves, respectively. With an estimated night-time latent heat flux of 24 W m^−2, tree transpiration significantly increased the cooling rate around and shortly after sunset, but not later in the night. Despite a strong midday latent heat flux of 206 W m^−2, a cooling effect of tree transpiration was not observed during the day.