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BACKGROUND Acetone is a volatile organic compound (VOC) that is often associated with poor air quality. Acetone has chronic toxicity towards humans and has significant impact to the overall atmospheric air quality. In this study, several layer double oxides (with M2+ = Mg, Ni, Co or Mn and M3+= Al or Ce)were tested as catalyst in acetone oxidation. RESULTS MnAl-LDO was found to be the most efficient catalyst. 50% acetone conversion was achieved at 170 °C (T50%) and 90% conversion at 200 °C (T90%).The incorporation of Ce on MnCeAl-LDO did not improve its catalytic properties over MnAl-LDO (the T50% for MnCeAl-LDO was 12 °C higher than for MnAl-LDO). The good performance on MnAl-LDO was due to the presence of Mn3+. MnAl-LDO was not affect when water was introduced into the catalytic reaction setup. Less than 5 % fluctuation in the acetone conversion rate at 170 and 200 °C was detected in the presence of 5.5% water. The incorporation of Ce on CoCeAl-LDO improved its catalytic performance over CoAl-LDO (T50% of CoCeAl-LDO was 15 °C lower than CoAl-LDO).Our results showed that the good catalytic performance of CoCeAl-LDO was ascribed to the increased Co2+/Co3+ ratio and the abundance of lattice oxygen (Olatt). CONCLUSION MnAl-LDO has good catalytic properties for acetone oxidation, even under humid conditions. The LDO catalysts tested here can be developed into efficient catalysts for acetone oxidation and serve as functional materials for the reduction in acetone or VOC emission. This article is protected by copyright. All rights reserved.

BACKGROUND Acetone is a volatile organic compound (VOC) that is often associated with poor air quality. Acetone has chronic toxicity towards humans and has significant impact to the overall atmospheric air quality. In this study, several layer double oxides (with M2+ = Mg, Ni, Co or Mn and M3+= Al or Ce)were tested as catalyst in acetone oxidation. RESULTS MnAl-LDO was found to be the most efficient catalyst. 50% acetone conversion was achieved at 170 °C (T50%) and 90% conversion at 200 °C (T90%).The incorporation of Ce on MnCeAl-LDO did not improve its catalytic properties over MnAl-LDO (the T50% for MnCeAl-LDO was 12 °C higher than for MnAl-LDO). The good performance on MnAl-LDO was due to the presence of Mn3+. MnAl-LDO was not affect when water was introduced into the catalytic reaction setup. Less than 5 % fluctuation in the acetone conversion rate at 170 and 200 °C was detected in the presence of 5.5% water. The incorporation of Ce on CoCeAl-LDO improved its catalytic performance over CoAl-LDO (T50% of CoCeAl-LDO was 15 °C lower than CoAl-LDO).Our results showed that the good catalytic performance of CoCeAl-LDO was ascribed to the increased Co2+/Co3+ ratio and the abundance of lattice oxygen (Olatt). CONCLUSION MnAl-LDO has good catalytic properties for acetone oxidation, even under humid conditions. The LDO catalysts tested here can be developed into efficient catalysts for acetone oxidation and serve as functional materials for the reduction in acetone or VOC emission. This article is protected by copyright. All rights reserved.

BACKGROUND Acetone is a volatile organic compound (VOC) that is often associated with poor air quality. Acetone has chronic toxicity towards humans and has significant impact to the overall atmospheric air quality. In this study, several layer double oxides (with M2+ = Mg, Ni, Co or Mn and M3+= Al or Ce)were tested as catalyst in acetone oxidation. RESULTS MnAl-LDO was found to be the most efficient catalyst. 50% acetone conversion was achieved at 170 °C (T50%) and 90% conversion at 200 °C (T90%).The incorporation of Ce on MnCeAl-LDO did not improve its catalytic properties over MnAl-LDO (the T50% for MnCeAl-LDO was 12 °C higher than for MnAl-LDO). The good performance on MnAl-LDO was due to the presence of Mn3+. MnAl-LDO was not affect when water was introduced into the catalytic reaction setup. Less than 5 % fluctuation in the acetone conversion rate at 170 and 200 °C was detected in the presence of 5.5% water. The incorporation of Ce on CoCeAl-LDO improved its catalytic performance over CoAl-LDO (T50% of CoCeAl-LDO was 15 °C lower than CoAl-LDO).Our results showed that the good catalytic performance of CoCeAl-LDO was ascribed to the increased Co2+/Co3+ ratio and the abundance of lattice oxygen (Olatt). CONCLUSION MnAl-LDO has good catalytic properties for acetone oxidation, even under humid conditions. The LDO catalysts tested here can be developed into efficient catalysts for acetone oxidation and serve as functional materials for the reduction in acetone or VOC emission. This article is protected by copyright. All rights reserved.

BACKGROUND Acetone is a volatile organic compound (VOC) that is often associated with poor air quality. Acetone has chronic toxicity towards humans and has significant impact to the overall atmospheric air quality. In this study, several layer double oxides (with M2+ = Mg, Ni, Co or Mn and M3+= Al or Ce)were tested as catalyst in acetone oxidation. RESULTS MnAl-LDO was found to be the most efficient catalyst. 50% acetone conversion was achieved at 170 °C (T50%) and 90% conversion at 200 °C (T90%).The incorporation of Ce on MnCeAl-LDO did not improve its catalytic properties over MnAl-LDO (the T50% for MnCeAl-LDO was 12 °C higher than for MnAl-LDO). The good performance on MnAl-LDO was due to the presence of Mn3+. MnAl-LDO was not affect when water was introduced into the catalytic reaction setup. Less than 5 % fluctuation in the acetone conversion rate at 170 and 200 °C was detected in the presence of 5.5% water. The incorporation of Ce on CoCeAl-LDO improved its catalytic performance over CoAl-LDO (T50% of CoCeAl-LDO was 15 °C lower than CoAl-LDO).Our results showed that the good catalytic performance of CoCeAl-LDO was ascribed to the increased Co2+/Co3+ ratio and the abundance of lattice oxygen (Olatt). CONCLUSION MnAl-LDO has good catalytic properties for acetone oxidation, even under humid conditions. The LDO catalysts tested here can be developed into efficient catalysts for acetone oxidation and serve as functional materials for the reduction in acetone or VOC emission. This article is protected by copyright. All rights reserved.

BACKGROUND Acetone is a volatile organic compound (VOC) that is often associated with poor air quality. Acetone has chronic toxicity towards humans and has significant impact to the overall atmospheric air quality. In this study, several layer double oxides (with M2+ = Mg, Ni, Co or Mn and M3+= Al or Ce)were tested as catalyst in acetone oxidation. RESULTS MnAl-LDO was found to be the most efficient catalyst. 50% acetone conversion was achieved at 170 °C (T50%) and 90% conversion at 200 °C (T90%).The incorporation of Ce on MnCeAl-LDO did not improve its catalytic properties over MnAl-LDO (the T50% for MnCeAl-LDO was 12 °C higher than for MnAl-LDO). The good performance on MnAl-LDO was due to the presence of Mn3+. MnAl-LDO was not affect when water was introduced into the catalytic reaction setup. Less than 5 % fluctuation in the acetone conversion rate at 170 and 200 °C was detected in the presence of 5.5% water. The incorporation of Ce on CoCeAl-LDO improved its catalytic performance over CoAl-LDO (T50% of CoCeAl-LDO was 15 °C lower than CoAl-LDO).Our results showed that the good catalytic performance of CoCeAl-LDO was ascribed to the increased Co2+/Co3+ ratio and the abundance of lattice oxygen (Olatt). CONCLUSION MnAl-LDO has good catalytic properties for acetone oxidation, even under humid conditions. The LDO catalysts tested here can be developed into efficient catalysts for acetone oxidation and serve as functional materials for the reduction in acetone or VOC emission. This article is protected by copyright. All rights reserved.

Two fundamental issues surrounding research on Zipf’s law regarding city sizes are whether and why this law holds. This paper does not deal with the latter issue with respect to why, and instead investigates whether Zipf’s law holds in a global setting, thus involving all cities around the world. Unlike previous studies, which have mainly relied on conventional census data such as populations and census-bureau-imposed definitions of cities, we adopt naturally (in terms of data speak for itself) delineated cities, or natural cities, to be more precise, in order to examine Zipf’s law. We find that Zipf’s law holds remarkably well for all natural cities at the global level, and it remains almost valid at the continental level except for Africa at certain time instants. We further examine the law at the country level, and note that Zipf’s law is violated from country to country or from time to time. This violation is mainly due to our limitations; we are limited to individual countries, or to a static view on city-size distributions. The central argument of this paper is that Zipf’s law is universal, and we therefore must use the correct scope in order to observe it. We further find Zipf’s law applied to city numbers; the number of cities in the largest country is twice as many as that in the second largest country, three times as many as that in the third largest country, and so on. These findings have profound implications for big data and the science of cities.

Carbon dioxide removal from flue gas via swing adsorption processes requires adsorbents with a high CO2 selectivity and capacity. These properties are particularly valuable to reduce the cost of carbon capture and storage (CCS). Zeolite NaKA was studied for its ability to selectively adsorb CO2 from flue gas, as we previously observed that zeolite NaKA, with a K+/(K+ + Na+) ratio of 17 atomic%, was highly selective towards CO2 over N2 adsorption by tuning the size of the pore window apertures [1]. The reduced pore apertures may, however, retard the adsorption rate of CO2. Here, we studied the kinetics of CO2 adsorption on regularly sized zeolite NaKA and on nano-sized zeolite NaKA. We used in situ infrared (IR) spectroscopy and observed that CO2 physisorbed relatively rapidly. Density functional theory (DFT) was used for quantum chemical calculations, and the results indicated that CO2 molecules bridged across two or three Na+ ions in the samples with no or very small amount of K+. When more K+ ions are present the CO2 molecules no longer bridged across multiple metal ions and adopted an end-on configuration. The calculation showed a shift in the stretching vibration frequency of physisorbed CO2 as observed by IR spectroscopy. Nano-sized zeolite NaKA were synthesised and studied to improve the rate of CO2 adsorption, as the diffusion rate typically increases quadratically with decreasing particle size. Still, the CO2 adsorption rate on nano-sized zeolites NaA and NaKA did not increase significantly. For nano-sized zeolite NaA, we speculate that the absence of such an increased rate is an effect from a skin layer that had formed on the nano-sized zeolite NaA, a layer that was possibly related to intergrowths with extremely small crystals on the surface. The apparently slow adsorption kinetics of CO2 on nano-sized zeolite NaKA was more difficult to explain because it could relate to imperfections within the small crystals, remaining water, or other effects. Overall, t

Carbon dioxide removal from flue gas via swing adsorption processes requires adsorbents with a high CO2 selectivity and capacity. These properties are particularly valuable to reduce the cost of carbon capture and storage (CCS). Zeolite NaKA was studied for its ability to selectively adsorb CO2 from flue gas, as we previously observed that zeolite NaKA, with a K+/(K+ + Na+) ratio of 17 atomic%, was highly selective towards CO2 over N-2 adsorption by tuning the size of the pore window apertures [1]. The reduced pore apertures may, however, retard the adsorption rate of CO2. Here, we studied the kinetics of CO2 adsorption on regularly sized zeolite NaKA and on nano-sized zeolite NaKA. We used in situ infrared (IR) spectroscopy and observed that CO2 physisorbed relatively rapidly. Density functional theory (DFT) was used for quantum chemical calculations, and the results indicated that CO2 molecules bridged across two or three Na+ ions in the samples with no or very small amount of K. When more K+ ions are present the CO2 molecules no longer bridged across multiple metal ions and adopted an end-on configuration. The calculation showed a shift in the stretching vibration frequency of physisorbed CO2 as observed by IR spectroscopy. Nano-sized zeolite NaKA were synthesised and studied to improve the rate of CO2 adsorption, as the diffusion rate typically increases quadratically with decreasing particle size. Still, the CO2 adsorption rate on nano-sized zeolites NaA and NaKA did not increase significantly. For nano-sized zeolite NaA, we speculate that the absence of such an increased rate is an effect from a skin layer that had formed on the nano-sized zeolite NaA, a layer that was possibly related to intergrowths with extremely small crystals on the surface. The apparently slow adsorption kinetics of CO2 on nano-sized zeolite NaKA was more difficult to explain because it could relate to imperfections within the small crystals, remaining water, or other effects. Overall, t, AuthorCount:5

Detecting the changes of land use and land cover of the earth’s surface is extremely important to achieve continual and precise information about study area for any kinds of planning of the development. Geographic information system and remote sensing technologies have shown their great capabilities to solve the study issues like land use and land cover changes. The aim of this thesis is to produce maps of land use and land cover of Shijiazhuang on year 1993, 2000 and 2009 to monitor the possible changes that may occur particularly in agricultural land and urban or built-up land, and detect the process of urbanization in this city. Three multi-temporal satellite image data, Thematic Mapper image data from year 1993, Enhanced Thematic Mapper image data from 2000 and China Brazil Earth Resource Satellite image data from 2009 were used in this thesis. In this study, supervised classification was the major classification approach to provide classified maps, and five land use and land cover categories were identified and mapped. Post-classification approach was used to improve the qualities of the classified map. The noises in the classified maps will be removed after post-classification process. Normalized difference vegetation index was used to detect the changes of vegetated land and non-vegetated land. Change detection function in Erdas Imagine was used to detect the urban growth and the intensity of changes surrounding the urban areas. Cellular automata Markov was used to simulate the trends of land use and cover change during the period of 1993 to 2000 and 2000 to 2009, and a future land use map was simulated based on the land use maps of year 2000 and 2009. From this performance, the cross-tabulation matrices between different periods were produced to analyze the trends of land use and cover changes, and these statistic data directly expressed the change of land use and land cover. The results show that the agricultural land and urban or built-up land were changed

The boundaries of the cities are not immutable, they can be changed. With the development of the economies and societies, the population and pollution of cities are increasing. Some urban areas are expanding with more population or other dynamics of urbanization, while other urban areas are reducing with the changing of the dynamics. Therefore, detecting urban areas or delineating the boundaries of the cities is one of the most important steps for urban studies, which is closely related to human settlements and human activities. Remote sensing data (RS) is widely used to monitor and detect land use and land cover on the surface of the earth. But the extraction of urban areas from the ordinary RS data is not easy work. The Operational Linescan System (OLS) is the sensors of the Defense Meteorological Satellite Program (DMSP). The nighttime lights from the DMSP/OLS provide worldwide remotely sensed data to analyze long-term light emissions which are closely related to human activities. But the nighttime lights imagery data contains inherent errors. Therefore, the approaches to calibrate the data and extract the urban areas from the data are complicated. The long-term objective of this thesis is to delineate the boundaries of the natural cities of the continental United States of America (USA) from 1992 to 2010 of nightlight imagery data with all the different satellites. In this thesis, the coefficients for the intercalibration of the nightlight imagery data have been calculated based on the method developed by Elvidge, et al. (2009), but the coefficients are new and available. The approach used to determine the most appropriate threshold value is very important to eliminate the possible data error. The method to offset this possible error and delineate the boundaries of the cities from nightlight imagery data is the head/tail breaks classification, which is proposed by Jiang (2012b). The head/tail breaks classification is also useful for finding the ht-index of the e

The boundaries of the cities are not immutable, they can be changed. With the development of the economies and societies, the population and pollution of cities are increasing. Some urban areas are expanding with more population or other dynamics of urbanization, while other urban areas are reducing with the changing of the dynamics. Therefore, detecting urban areas or delineating the boundaries of the cities is one of the most important steps for urban studies, which is closely related to human settlements and human activities. Remote sensing data (RS) is widely used to monitor and detect land use and land cover on the surface of the earth. But the extraction of urban areas from the ordinary RS data is not easy work. The Operational Linescan System (OLS) is the sensors of the Defense Meteorological Satellite Program (DMSP). The nighttime lights from the DMSP/OLS provide worldwide remotely sensed data to analyze long-term light emissions which are closely related to human activities. But the nighttime lights imagery data contains inherent errors. Therefore, the approaches to calibrate the data and extract the urban areas from the data are complicated. The long-term objective of this thesis is to delineate the boundaries of the natural cities of the continental United States of America (USA) from 1992 to 2010 of nightlight imagery data with all the different satellites. In this thesis, the coefficients for the intercalibration of the nightlight imagery data have been calculated based on the method developed by Elvidge, et al. (2009), but the coefficients are new and available. The approach used to determine the most appropriate threshold value is very important to eliminate the possible data error. The method to offset this possible error and delineate the boundaries of the cities from nightlight imagery data is the head/tail breaks classification, which is proposed by Jiang (2012b). The head/tail breaks classification is also useful for finding the ht-index of the e

Detecting the changes of land use and land cover of the earth’s surface is extremely important to achieve continual and precise information about study area for any kinds of planning of the development. Geographic information system and remote sensing technologies have shown their great capabilities to solve the study issues like land use and land cover changes. The aim of this thesis is to produce maps of land use and land cover of Shijiazhuang on year 1993, 2000 and 2009 to monitor the possible changes that may occur particularly in agricultural land and urban or built-up land, and detect the process of urbanization in this city. Three multi-temporal satellite image data, Thematic Mapper image data from year 1993, Enhanced Thematic Mapper image data from 2000 and China Brazil Earth Resource Satellite image data from 2009 were used in this thesis. In this study, supervised classification was the major classification approach to provide classified maps, and five land use and land cover categories were identified and mapped. Post-classification approach was used to improve the qualities of the classified map. The noises in the classified maps will be removed after post-classification process. Normalized difference vegetation index was used to detect the changes of vegetated land and non-vegetated land. Change detection function in Erdas Imagine was used to detect the urban growth and the intensity of changes surrounding the urban areas. Cellular automata Markov was used to simulate the trends of land use and cover change during the period of 1993 to 2000 and 2000 to 2009, and a future land use map was simulated based on the land use maps of year 2000 and 2009. From this performance, the cross-tabulation matrices between different periods were produced to analyze the trends of land use and cover changes, and these statistic data directly expressed the change of land use and land cover. The results show that the agricultural land and urban or built-up land were changed

Adsorption-driven separation of CO2 from flue gas has the potential to cut the cost for carbon capture and storage. Among the porous physisorbents, metal-organic frameworks (MOFs) are a class of promising candidates for gas separation and storage owing to their extraordinarily high specific surface areas and pore volumes, and predesigned pore structures. Here, we report three interpenetrated MOFs composed of Zn4O clusters and rigid dicarboxylate anions, namely SUMOF-n (SU StockholmUniversity; n = 2, 3, 4). All the interpenetrated MOFs possess small pores of two different types and high pore volumes. SUMOF-2 had a structure similar to interpenetrated MOF-5, but with an extra-framework cation present in one of the two types of pores. SUMOF-3 was an interpenetrated version of IRMOF-8 while SUMOF-4 crystallized with mixed linkers, biphenyl-4,4'-dicarboxylic acid and benzene-1,4-dicarboxylic acid. Among the three SUMOFs, SUMOF-4 had the largest specific surface area (1612 m(2) g(-1)) and pore volume. Single component adsorption of CO2 and N-2 was determined at 273 K. We showed that the interpenetrated SUMOF-2 adsorbedmore CO2 than non-interpenetrated MOF-5 under 273 K and 1 bar. This may be explained by the increased electric field gradients due to the interpenetration in the MOF. The uptake of CO2 for SUMOF-2 and SUMOF-4 was significant at somewhat higher pressure. Their CO2 isotherms were close to linear, which could be beneficial for separation of CO2 via pressure swing adsorption from biogas or natural gas. On the other hand, SUMOF-3 adsorbed most CO2 at pressures relevant for CO2 capture from flue gas., AuthorCount:6

Silicoaluminophosphates (SAPO-17, SAPO-35, SAPO-56 and SAPO-RHO) synthesised via hydrothermal means are tested for their abilities to adsorb carbon dioxide. These 8-ring microporous phosphates show high capacities to adsorb CO2. SAPO-RHO has a high uptake of CO2 and a very low uptake of N-2 due to its narrow pore window aperture at 273 K. Its significant uptake of N-2 at 77 K is rationalised by a temperature induced shrinkage effect. SAPO-56 has a slightly higher CO2 capacity (5.42 mmol/g, 273 K, 101 kPa) and is less water sensitive than zeolite 13X. Cyclic adsorption and in situ infrared spectroscopy (IR) reveal that SAPOs retain 95% of their original CO2 capacity after six cycles and that adsorption occurs via physisorption. The calculated heat of adsorption for CO2 (at 0.2-0.7 mmol/g loading) on SAPO-56 and SAPO-RHO lies in the physisorption range (similar to 35 kJ/mol). SAPOs, in particular SAPO-56 and SAPO-RHO, possess many desirable properties and are potentially good adsorbents for CO2 capture in swing adsorption processes., AuthorCount:4

Mechanically strong monoliths of zeolite NaKA with a hierarchy of pores displayed very high CO2-over-N-2 selectivity. The zeolite monoliths were produced by pulsed current processing (PCP) without the use of added binders and with a preserved microporous crystal structure. Adsorption isotherms of CO2 and N-2 were determined and used to predict the co-adsorption of CO2 and N-2 using ideal adsorbed solution theory (IAST). The IAST predictions showed that monolithic adsorbents of NaKA could reach an extraordinarily high CO2-over-N-2 selectivity in a binary mixture with a composition similar to flue gas (15 mol% CO2 and 85 mol% N2 at 25 degrees C and 101 kPa). Structured NaKA monoliths with a K+ content of 9.9 at% combined a CO2-over-N-2 selectivity of >1100 with a high CO2 adsorption capacity (4 mmol g(-1)) and a fast adsorption kinetics (on the order of one minute). Estimates of a figure of merit (F) based on IAST CO2-over-N-2 selectivity, and time-dependent CO2 uptake capacity, suggest that PCP-produced structured NaKA with a K+ content of 9.9 at% offers a performance far superior to 13X adsorbents, in particular at short cycle times., AuthorCount:4

The pressure-swing adsorption method for carbon dioxide capture would ideally be facilitated by adsorbents with a high capacity and a high selectivity for CO2. Several aluminophosphates with 8-ring window apertures (AlPO4-17, AlPO4-18, AlPO4-53, and AlPO4-25) were synthesized by hydrothermal crystallization, calcined, and their CO2 uptake and CO2/N-2 selectivity were studied. CO2 and N-2 uptake was determined for pressures up to 101 kPa at 273 and 293 K. Langmuir and Toth adsorption models were used to describe the adsorption isotherms. The CO2 and N-2 uptakes strongly indicated that the squeezed 8-ring windows of certain aluminophosphates can sieve CO2 from a CO2 and N-2 gas mixture. Both AlPO4-53 and AlPO4-25 exhibited a remarkably higher uptake of CO2 compared to N-2. The hydrophilicity of the AlPO4 materials was investigated by means of water adsorption, and the results showed that all of the tested aluminophosphates were less water sensitive than a benchmark zeolite (13X). In particular, AlPO4-53 and AlPO4-25 showed a very low degree of water uptake with up to 20-30% relative humidity. Determination of cyclic adsorption and desorption confirmed the relatively hydrophobic nature of the aluminophosphates, which render them less energy costly for the regeneration of adsorbents.

The pressure-swing adsorption method for carbon dioxide capture would ideally be facilitated by adsorbents with a high capacity and a high selectivity for CO(2). Several aluminophosphates with 8-ring window apertures (AlPO(4)-17, AlPO(4)-18, AlPO(4)-53, and AlPO(4)-25) were synthesized by hydrothermal crystallization, calcined, and their CO(2) uptake and CO(2)/N(2) selectivity were studied. CO(2) and N(2) uptake was determined for pressures up to 101 kPa at 273 and 293 K. Langmuir and Toth adsorption models were used to describe the adsorption isotherms. The CO(2) and N(2) uptakes strongly indicated that the squeezed 8-ring windows of certain aluminophosphates can sieve CO(2) from a CO(2) and N(2) gas mixture. Both AlPO(4)-53 and AlPO(4)-25 exhibited a remarkably higher uptake of CO(2) compared to N(2). The hydrophilicity of the AlPO(4) materials was investigated by means of water adsorption, and the results showed that all of the tested aluminophosphates were less water sensitive than a benchmark zeolite (13X). In particular, AlPO(4)-53 and AlPO(4)-25 showed a very low degree of water uptake with up to 20-30% relative humidity. Determination of cyclic adsorption and desorption confirmed the relatively hydrophobic nature of the aluminophosphates, which render them less energy costly for the regeneration of adsorbents., authorCount :4

The uptake of carbon dioxide and nitrogen gas by zeolite NaKA was studied. A very high ideal CO2-over-N2 selectivity and a high CO2 capacity were observed at an optimal K+ content of 17 at.%. NaKA is a very promising adsorbent for CO2 separation from water-free flue gases.