Near infrared reflectance (N1R) spectroscopy is as a rapid, convenient and simple nondestructive technique useful for quantifying several soil properties. This method was used to estimate nitrogen (N) and organic ...Near infrared reflectance (N1R) spectroscopy is as a rapid, convenient and simple nondestructive technique useful for quantifying several soil properties. This method was used to estimate nitrogen (N) and organic matter (OM) content in a soil of Zhejiang Province, Hangzhou County. A total of 125 soil samples were taken from the field. Ninety-five samples spectra were used during the calibration and cross validation stage. Thirty samples spectra were used to predict N and OM concentration. NIR spectra of these samples were correlated using partial least square regression. The regression coefficients between measured and predicted values of N and OM was 0.92 and 0.93, and SEP (standard error of prediction) were 3.28 and 0.06, respectively, which showed that NIR method had potential to accurately predict these constituents in this soil. The results showed that NIR spectroscopy could be a good tool for precision farming application.展开更多
This study on the temporal and spatial variability of the viscosity and some chemical parameters in the sea surface microlayer (SML), the relationship between the viscosity and chemical parameters, and the influence o...This study on the temporal and spatial variability of the viscosity and some chemical parameters in the sea surface microlayer (SML), the relationship between the viscosity and chemical parameters, and the influence of the viscosity on the mass transfer coefficient ( K ) in the flux of materials through the air sea interface revealed that: The values of viscosity and some chemical parameters in the SML are higher than those in the sub surface layer (SSL), and at daytime are higher than those at night. The viscosity has positive corelation with chemical oxygen demand (COD), dissolved organic carbon (DOC) and salinity. The "SML effect" on K need not be considered because the SML effect on materials concentration is so small.展开更多
Responses of the Asian Summer Monsoon(ASM) in future projections have been studied based on two core future projections of phase five of the Coupled Model Intercomparison Project(CMIP5) coordinated experiments with th...Responses of the Asian Summer Monsoon(ASM) in future projections have been studied based on two core future projections of phase five of the Coupled Model Intercomparison Project(CMIP5) coordinated experiments with the IAP-coupled model FGOALS_s2(the Flexible Global Ocean-Atmosphere-Land System Model).The projected changes of the ASM in climatological mean and interannual variability were respectively reported.Both the South Asian Summer Monsoon(SASM) and the East Asian Summer Monsoon(EASM) were intensified in their climatology,featuring increased monsoon precipitation and an enhanced monsoon lower-level westerly jet flow.Accordingly,the amplitude of the annual cycle of rainfall over East Asia(EA) is enhanced,thereby indicating a more abrupt monsoon onset.After the EA monsoon onset,the EASM marched farther northward in the future scenarios than in the historical runs.In the interannual variability,the leading pattern of the EASM,defined by the first multi-variable EOF analysis over EA,explains more of the total variances in the warmest future scenario,specifically,Representative Concentration Pathway(RCP8.5).Also,the correlation coefficients analysis suggests that the relationship between the EASM interannual variations and ENSO was significantly strengthened in the future projections,which may indicate improved predictability of the EASM interannual variations.展开更多
A new land cover classification system was established for the Three Gorges Reservoir Region(TGRR) after considering the continuity of inundation and the natural characteristics of land cover. The potential evapotrans...A new land cover classification system was established for the Three Gorges Reservoir Region(TGRR) after considering the continuity of inundation and the natural characteristics of land cover. The potential evapotranspiration(PET) was predicted using a modified Penman-Monteith(P-M) model. The region's ratio of precipitation to evapotranspiration was calculated as the humidity index(HI). The data obtained was used to analyze climatic responses to land cover conversions from the perspectives of evapotranspiration and humidity variations. The results show that, from 1997 to 2009, the average annual PET increased in the early years and decreased later. In terms of overall spatial distribution, a significant reciprocal relationship appeared between annual PET and annual HI. In 1997,the annual PET was higher in the lower reaches than in the upper reaches of the TGRR, but the areas with high PET shifted substantially westward by 2003. The annual PET continued to increase in 2006, but the areas with high PET shrank by 2009. In contrast, the annual HI showed varying degrees of localized spatial variability. Over the three periods, the dominantforms of land cover conversions occurred from evergreen cover to seasonal green cover, from seasonal green cover to evergreen cover, and from seasonal green cover to seasonally inundated areas, respectively. These accounted for 48.0%, 38.4%, and 23.8% of the total areas of converted land covers in the three periods, respectively. During the period between 1997 and 2003, the main forms of land cover conversions resulted in both positive and negative growths in the average annual PET, while all of them pushed down the average annual HI. From 2003 to 2006, the reservoir region experienced neither a decrease in the annual PET nor an increase in the annual HI. The period between 2006 and 2009 saw a consistent downward trend in the annual PET and a consistent upward trend in the annual HI.展开更多
We give the generalized definitions of variable separable solutions to nonlinear evolution equations, and characterize the relation between the functional separable solution and the derivative-dependent functional sep...We give the generalized definitions of variable separable solutions to nonlinear evolution equations, and characterize the relation between the functional separable solution and the derivative-dependent functional separable solution. The new definitions can unify various kinds of variable separable solutions appearing in references. As application, we classify the generalized nonlinear diffusion equations that admit special functional separable solutions and obtain some exact solutions to the resulting equations.展开更多
The study aimed at addressing climate variability impacts on wheat and barley production in Palestine. A combination of literature survey and multiple semi-structured interviews with officials from the Palestinian gov...The study aimed at addressing climate variability impacts on wheat and barley production in Palestine. A combination of literature survey and multiple semi-structured interviews with officials from the Palestinian governmental agriculture related agencies and active non-governmental organizations (NGOs) used for gathering information on wheat and barley production in Palestine. The gathered data along with information and subsequent results prevailed that the West Bank since the 1970s has experienced a significant decrease in winter rainfall. Across 15 sites, growing season rainfall (September to May) decreased by an average of 11% and the sum of rainfall in September and October decreased by 45%. Despite the large decline in rainfall, yields based on the actual weather data did not fall. These results were due to the rainfall changes mainly occurring in September and October, a period when rainfall often is less than crop demand. The study arrived at conclusion based on the study results that climate change variabilities have differential impacts on the yield growth of wheat and barley. However, both rainfed dependent crops are adversely affected by the current climate trends. The yields of barley and wheat are decreasing due to increased temperature and decreased precipitation.展开更多
Mountain regions are sensitive to climate changes, which make them good indicators of climate change. The aim of this study is to investigate the spatial and temporal variability of air temperature and precipitation i...Mountain regions are sensitive to climate changes, which make them good indicators of climate change. The aim of this study is to investigate the spatial and temporal variability of air temperature and precipitation in the Polish Carpathians. This study consists of climatological analyses for the historical period 1851-2010 and future projections for 2021-2100. The results confirm that there has been significant warming of the area and that this warming has been particularly pronounced over the last few decades and will continue in the oncoming years.Climate change is most evident in the foothills;however, these are the highest summits which have experienced the most intensive increases in temperature during the recent period. Precipitation does not demonstrate any substantial trend and has high year-to-year variability. The distribution of the annual temperature contour lines modelled for selected periods provides evidence of the upward shift of vertical climate zones in the Polish Carpathians,which reach approximately 350 meters, on average,what indicates further ecological consequences as ecosystems expand or become extinct and when there are changes in the hydrological cycle.展开更多
This paper researches the ecological sustainability of Zhangjiakou City, Hebei Province, China, using the ecological footprint model. According to the study we find that Zhangjiakou City was in the situation of ecolog...This paper researches the ecological sustainability of Zhangjiakou City, Hebei Province, China, using the ecological footprint model. According to the study we find that Zhangjiakou City was in the situation of ecological deficit from 1990 to 2000 and the deficit had the enlarging tendency. In 1990 the per capita ecological footprint was 0.964 and the per capita ecological capacity was 0.5 l 8, thus it can be calculated that the per capita ecological deficit was 4).446. However in 2000, the per capita ecological footprint increased to 1.068, at the same time the per capita eco- logical capacity decreased to 0.471, then the per capita ecological deficit in 2000 was 4).597. Furthermore, this paper studies the ecological sustainability of the city from the changes of the ecological footprint of per 10,000 yuan GDP and the productivity of ecological system. Finally the authors point out the shortage of the model and the way to improve it.展开更多
A series of Poly(arly ether sulfone ether ketone)s containing pendant methyl groups were synthesized by the reaction of 4,4'-[sulfonylbis (1,4-phenylene)dioxy] dibenzoyl chloride (SODBC) with 4,4'- diphenoxy d...A series of Poly(arly ether sulfone ether ketone)s containing pendant methyl groups were synthesized by the reaction of 4,4'-[sulfonylbis (1,4-phenylene)dioxy] dibenzoyl chloride (SODBC) with 4,4'- diphenoxy diphenylsulfone (DPODPS), 4,4'- di(2-methylphenoxy) diphenylsulfone (o-Me-DPODPS), 4,4'- di(3-methylphenoxy) diphenylsulfone (m-Me-DPODPS), 4,4'- di (2,6-bimethylphenoxy) biphenylsulfone(o-Me2-DPODPS) respectively, in a mixture of 1,2-dichloroethane (DCE) and N-methylpyrrolidone (NMP). These reactions were catalyzed by anhydrous aluminum chloride (AlCl). The characteristic of copolymers were studied by means of advanced analytical techniques such as FT-IR,1H-NMR, DSC, TGA and WAXD. The results show glass transition temperature (Tg) in the range of 193-206℃, thermally stable in excess of 434℃ and excellent solubility in polar solvents. Methyl-substituted Poly(aryl ether sulfone ketone)s had higher glass transition temperatures, lower initial decomposition temperatures than the unsubstituted ones.展开更多
Global changes, including the rise of the sea level and frequent terrible disasters, are apparently threatening the living environment. For environmental mitigation, security, and sustainability, Taiwan should have re...Global changes, including the rise of the sea level and frequent terrible disasters, are apparently threatening the living environment. For environmental mitigation, security, and sustainability, Taiwan should have reliable, incorporative area-based security-information networks to protect their environments. Plural (dual) surveillance which is rooted in biologic senses, e.g., from two-eyes, can have the feature of fault-tolerance, availability and maintainability in monitoring tasks. Further, it can fit the contemporary wireless communication methods being incorporated with MIMO (multi-in multi-out), to prevent information loss, interference, unexpected changes caused by such as clogged water and chemical reactions. Consequently, network prototypes, including SW (spider-web)network and CCC (cube-connected cycle), are proactively suggested. More reliable capabilities, including those encouraging local ferries and drones, for efficient logistic operation and mixed-use buildings with quality assured performance, can be good for smart urban growth, resource utilization in Taiwan, which is aimed as an aerotropolis--a means for placemaking.展开更多
Xiashu loess strata are widely distributed along the middle-lower reaches of the Yangtze River in East China with the stratum near Nanjing,Jiangsu Province being typical.The cyclic variability of the stratum was inves...Xiashu loess strata are widely distributed along the middle-lower reaches of the Yangtze River in East China with the stratum near Nanjing,Jiangsu Province being typical.The cyclic variability of the stratum was investigated through comparison of geological features,chemical composition,and swelling-shrinkage properties between the loess and the paleosol layers.Based on the investigation of such a cyclic variability,soil behavior associated with the unsaturated state of the Xiashu loess stratum and its usefulness for geotechnical design and construction in the Nanjing area was analyzed. The stratum consisted of two types of cyclically alternating soil layers,namely the loess and the paleosol layers,which was the major cause for its cyclic variability.The loess and the paleosol layers were formed in different sedimentary environments.In order to avoid detrimental results from the differential engineering properties between them,this study suggested for the practitioners the importance of inspecting the variation of water content and controlling the downward net fluxes during geotechnical construction in the Nanjing area.展开更多
Severe water erosion is notorious for its harmful effects on land-water resources as well as local societies. The scale effects of water erosion, however, greatly exacerbate the difficulties of accurate erosion evalua...Severe water erosion is notorious for its harmful effects on land-water resources as well as local societies. The scale effects of water erosion, however, greatly exacerbate the difficulties of accurate erosion evaluation and hazard control in the real world. Analyzing the related scale issues is thus urgent for a better understanding of erosion variations as well as reducing such erosion. In this review article, water erosion dynamics across three spatial scales including plot, watershed, and regional scales were selected and discussed. For the study purposes and objectives, the advantages and disadvantages of these scales all demonstrate clear spatial-scale dependence. Plot scale studies are primarily focused on abundant data collection and mechanism discrimination of erosion generation, while watershed scale studies provide valuable information for watershed management and hazard control as well as the development of quantitatively distributed models. Regional studies concentrate more on large-scale erosion assessment, and serve policymakers and stakeholders in achieving the basis for regulatory policy for comprehensive land uses. The results of this study show that the driving forces and mechanisms of water erosion variations among the scales are quite different. As a result, several major aspects contributing to variations in water erosion across the scales are stressed: differences in the methodologies across various scales, different sink-source roles on water erosion processes, and diverse climatic zones and morphological regions. This variability becomes more complex in the context of accelerated global change. The changing climatic factors and earth surface features are considered the fourth key reason responsible for the increased variability of water erosion across spatial scales.展开更多
The radial deformation design of turbine disk seriously influences the control of gas turbine high pressure turbine(HPT) blade-tip radial running clearance(BTRRC). To improve the design of BTRRC under continuous opera...The radial deformation design of turbine disk seriously influences the control of gas turbine high pressure turbine(HPT) blade-tip radial running clearance(BTRRC). To improve the design of BTRRC under continuous operation, the nonlinear dynamic reliability optimization of disk radial deformation was implemented based on extremum response surface method(ERSM), including ERSM-based quadratic function(QF-ERSM) and ERSM-based support vector machine of regression(SR-ERSM). The mathematical models of the two methods were established and the framework of reliability-based dynamic design optimization was developed. The numerical experiments demonstrate that the proposed optimization methods have the promising potential in reducing additional design samples and improving computational efficiency with acceptable precision, in which the SR-ERSM emerges more obviously. Through the case study, we find that disk radial deformation is reduced by about 6.5×10–5 m; δ=1.31×10–3 m is optimal for turbine disk radial deformation design and the proposed methods are verified again. The presented efforts provide an effective optimization method for the nonlinear transient design of motion structures for further research, and enrich mechanical reliability design theory.展开更多
The Igbo language has grown and developed to what is known as Standard Igbo (Igbo Izugbe) today. Series of efforts have gone into the modification and invention of words to ensure wider acceptability and intelligibi...The Igbo language has grown and developed to what is known as Standard Igbo (Igbo Izugbe) today. Series of efforts have gone into the modification and invention of words to ensure wider acceptability and intelligibility While this is a welcome idea, the tendency of the loss of communal identity in terms of the original local variety of the Igbo Language spoken by each community becomes very obvious. As Igbos can easily distinguish an Anambra man from an Imo man, it is also necessary that within Arlambra, one should be able to locate a particular town in the area through the spoken Igbo Language variety. This paper studies some of these local variants and advocates for a method of preserving such rich cultural heritage which are so valuable for posterity展开更多
Athens, a metropolis characterized by agglutination and compactness, but at the same time facing numerous urban and transport issues, saw its population swell during the 20th century which led to extensive urbanizatio...Athens, a metropolis characterized by agglutination and compactness, but at the same time facing numerous urban and transport issues, saw its population swell during the 20th century which led to extensive urbanization phenomena. This continued urbanization increases profoundly all urban activities with transportation being the key driver in energy consumption. Theories for sustainable cities prerequisite are the integration of a number of acts in order to reduce energy consumption, with mobility being the first consideration among others. The aim of this paper is to critically explore implemented policies and plans as well as forthcoming strategic plans in terms of sustainable mobility as imposed in large scale regeneration plans in contemporary Athens. Research focuses on strategic interventions since the 1980s, such as the Athenian Daktylios (ring road for circulation management) and its later adjustments, the upcoming pedestrianization and unification of the commercial triangle and its subsequent tram line extension as well as the notable implementation of the metropolitan cycling network. Moreover, the discussion takes into consideration the implications of the Greek economic crisis in mobility choices, as aimless travels have been reduced to a minimum, several cars have been abandoned and cyclists seem to tentatively claim some space in the urban environment. What will likely be the next day in the Athenian historic centre? Considering the transformations that are expected in the immediate future, this research paper explores their potential to enhance urban environment, reduce climate change impacts and amplify resilience.展开更多
This study aimed at the physical, chemical and biochemical changes during ripening of Sweetsop (Annona squamosa L.) and Golden Apple (Spondias citherea Sonner) fruits during ripening as important features to bette...This study aimed at the physical, chemical and biochemical changes during ripening of Sweetsop (Annona squamosa L.) and Golden Apple (Spondias citherea Sonner) fruits during ripening as important features to better understand their postharvest handling. It was carried out physical analysis such as firmness and chemical analysis such as total chlorophyll, total carotenoids, soluble solids, pectins and titrable acidity and biochemical analysis such as pectin methyl esterase, polygalacturonase, cellulase, and peroxidase and polyphenoloxidase activities in crude extract. Fruits were harvested at different stages of ripening. Experimental design was completely randomized and was carried out analysis of variance and Tukey tests, Total chlorophyll was decreasing in later stages of ripening, total soluble solid contents increased as the fruits ripen, while the acidity expressed percentage of citric acid decreased during fruits ripening. The loss of firmness and soluble solids content increased as the fruit get ripped stage, while the content of pectin decreased. Activity was observed for pectin methyl esterase and polygalacturonase enzymes during all stages of maturation, presenting the highest activity for both enzymes in the mature state. No cellulase activity detected at any stage during the ripening of these fruits. Activity of the enzyme polyphenoloxidase and peroxidase, associated with pulp browning was higher in the last stages of ripening of these fruits. Physical, chemical and biochemical patterns during ripening were different according to fruit species suggesting differential postharvest handling requirements.展开更多
The processes of nutrient depletion and soil degradation within smallholder farms of central Kenya are spatially heterogeneous, determined by both biophysical and socio-economic factors. A monitoring study involving n...The processes of nutrient depletion and soil degradation within smallholder farms of central Kenya are spatially heterogeneous, determined by both biophysical and socio-economic factors. A monitoring study involving nutrient stocks, flows and balances was conducted in central Kenya to explore between and within-farm variability in soil fertility management and identify spatial niches for targeting soil fertility management strategies. Focus group discussions were conducted and farms grouped into 3 farm types (rich, medium and poor). Nine case-study farms - three from each of the farm types - were randomly selected from the 50 farms studied, for detailed resource flow mapping. The farms were visited to record movement of nutrients inputs using a monitoring protocol covering soil, crops, livestock, and socio-economic aspects of the farm. Soil in different plots were sampled at a depth of 0-20 cm and analyzed for texture, pH, C, N, available P, exchangeable K+, Mg2+ and Ca2+. Results revealed that wealthy farmers added an average of 51.3 kg/ha N, 37 kg/ha P, and 244 kg/ha K, compared to 25.9 kg/ha N, 14.5 kg/ha P and 50.7 kg/ha K for the poor farmers. In all farm types, home fields received more nutrient inputs compared to the outfields. Consequently, maize grain yields, partial nutrient balances and soil nutrient stocks were significantly higher in wealthy farms and home fields compared to poor farms and outfields, respectively. These results imply that different soil management strategies are required to achieve similar yields on the different field and farm types and avert soil degradation.展开更多
Lake Vrana on the island of Cres is one of the largest fresh water features on Mediterranean islands. The maximum depth of the lake is 72 m and it stores 220 million m3 of fresh water. The paper provides an overview o...Lake Vrana on the island of Cres is one of the largest fresh water features on Mediterranean islands. The maximum depth of the lake is 72 m and it stores 220 million m3 of fresh water. The paper provides an overview of lake and groundwater temperature measurements to date and recent activities within the EU project "CC-WaterS (Climate Change and Impacts on Water Supply)". Groundwater temperatures in the lake surrounding are almost constant throughout the year, in the range from 14.6 ℃ to 13.1 ℃, while thermodynamic cycle of the lake conforms to the characteristics of a monomictic, medium depth lake in the moderate climate belt. Present and future climate simulations using three limited area models were analyzed (Aladin, Promes and RegCM3), they pointed out further air temperature increase in range of 0.27 ℃/10 yrs to 0.32 ℃/10 yrs. The significant changes of precipitation rates were not indicated. Considering increasing water consumption from the lake, already asserted negative trends, indicated climate changes and possible effects on the lake recharge, it is necessary to establish continual monitoring of parameters that describe lake system behaviour and periodically analyze lake conditions, especially with respect to the extraction for the public water supply.展开更多
The most important achievement in the Paris Agreement is to set up emission reduction target by commitment submitted by each country/ region with the form INDC. However the emission reduction target inside INDCs could...The most important achievement in the Paris Agreement is to set up emission reduction target by commitment submitted by each country/ region with the form INDC. However the emission reduction target inside INDCs could not match with the emission pathway for the global to keep a global temperature rise this century well below 2 ℃ and to drive efforts to limit the temperature increase even further to 1.5 ℃ above pre- industrial levels. It is important for countries to do more than their commitment in INDCs, especially in near term. This paper looks at the near term trend for possibilities for further emission reduction compared with INDCs, and found there do have the possibility. It concludes there is space for the four countries/regions to do more than their INDCs submitted to UNFCCC, and see the light towards to a global 2 ℃ target.展开更多
基金Project supported by the National Natural Science Foundation of China (No. 30270773), and the Teaching and Research Award Pro-gram for Outstanding Young Teachers in Higher Education Institu-tions & the Specialized Research Fund for the Doctoral Program o
文摘Near infrared reflectance (N1R) spectroscopy is as a rapid, convenient and simple nondestructive technique useful for quantifying several soil properties. This method was used to estimate nitrogen (N) and organic matter (OM) content in a soil of Zhejiang Province, Hangzhou County. A total of 125 soil samples were taken from the field. Ninety-five samples spectra were used during the calibration and cross validation stage. Thirty samples spectra were used to predict N and OM concentration. NIR spectra of these samples were correlated using partial least square regression. The regression coefficients between measured and predicted values of N and OM was 0.92 and 0.93, and SEP (standard error of prediction) were 3.28 and 0.06, respectively, which showed that NIR method had potential to accurately predict these constituents in this soil. The results showed that NIR spectroscopy could be a good tool for precision farming application.
文摘This study on the temporal and spatial variability of the viscosity and some chemical parameters in the sea surface microlayer (SML), the relationship between the viscosity and chemical parameters, and the influence of the viscosity on the mass transfer coefficient ( K ) in the flux of materials through the air sea interface revealed that: The values of viscosity and some chemical parameters in the SML are higher than those in the sub surface layer (SSL), and at daytime are higher than those at night. The viscosity has positive corelation with chemical oxygen demand (COD), dissolved organic carbon (DOC) and salinity. The "SML effect" on K need not be considered because the SML effect on materials concentration is so small.
基金supported by the Chinese Acad-emy of Sciences (XDA05110303)the National Basic Research Program of China (973 Program,2012CB417203)the National Natural Science Foundation of China (40805038 and 41023002)
文摘Responses of the Asian Summer Monsoon(ASM) in future projections have been studied based on two core future projections of phase five of the Coupled Model Intercomparison Project(CMIP5) coordinated experiments with the IAP-coupled model FGOALS_s2(the Flexible Global Ocean-Atmosphere-Land System Model).The projected changes of the ASM in climatological mean and interannual variability were respectively reported.Both the South Asian Summer Monsoon(SASM) and the East Asian Summer Monsoon(EASM) were intensified in their climatology,featuring increased monsoon precipitation and an enhanced monsoon lower-level westerly jet flow.Accordingly,the amplitude of the annual cycle of rainfall over East Asia(EA) is enhanced,thereby indicating a more abrupt monsoon onset.After the EA monsoon onset,the EASM marched farther northward in the future scenarios than in the historical runs.In the interannual variability,the leading pattern of the EASM,defined by the first multi-variable EOF analysis over EA,explains more of the total variances in the warmest future scenario,specifically,Representative Concentration Pathway(RCP8.5).Also,the correlation coefficients analysis suggests that the relationship between the EASM interannual variations and ENSO was significantly strengthened in the future projections,which may indicate improved predictability of the EASM interannual variations.
基金partially supported and funded by Chongqing Research Program of Basic Research and Frontier Technology (Grant No. cstc2017jcyj B0317)Chongqing University Innovation Team Building Plan (Grant No. CXTDX201601017)Science and Technology Project of Chongqing Municipal Education Commission (Grant No. KJ1738462)
文摘A new land cover classification system was established for the Three Gorges Reservoir Region(TGRR) after considering the continuity of inundation and the natural characteristics of land cover. The potential evapotranspiration(PET) was predicted using a modified Penman-Monteith(P-M) model. The region's ratio of precipitation to evapotranspiration was calculated as the humidity index(HI). The data obtained was used to analyze climatic responses to land cover conversions from the perspectives of evapotranspiration and humidity variations. The results show that, from 1997 to 2009, the average annual PET increased in the early years and decreased later. In terms of overall spatial distribution, a significant reciprocal relationship appeared between annual PET and annual HI. In 1997,the annual PET was higher in the lower reaches than in the upper reaches of the TGRR, but the areas with high PET shifted substantially westward by 2003. The annual PET continued to increase in 2006, but the areas with high PET shrank by 2009. In contrast, the annual HI showed varying degrees of localized spatial variability. Over the three periods, the dominantforms of land cover conversions occurred from evergreen cover to seasonal green cover, from seasonal green cover to evergreen cover, and from seasonal green cover to seasonally inundated areas, respectively. These accounted for 48.0%, 38.4%, and 23.8% of the total areas of converted land covers in the three periods, respectively. During the period between 1997 and 2003, the main forms of land cover conversions resulted in both positive and negative growths in the average annual PET, while all of them pushed down the average annual HI. From 2003 to 2006, the reservoir region experienced neither a decrease in the annual PET nor an increase in the annual HI. The period between 2006 and 2009 saw a consistent downward trend in the annual PET and a consistent upward trend in the annual HI.
基金The project supported by National Natural Science Foundation of China under Grant Nos.10447007 and 10671156the Natural Science Foundation of Shaanxi Province of China under Grant No.2005A13
文摘We give the generalized definitions of variable separable solutions to nonlinear evolution equations, and characterize the relation between the functional separable solution and the derivative-dependent functional separable solution. The new definitions can unify various kinds of variable separable solutions appearing in references. As application, we classify the generalized nonlinear diffusion equations that admit special functional separable solutions and obtain some exact solutions to the resulting equations.
文摘The study aimed at addressing climate variability impacts on wheat and barley production in Palestine. A combination of literature survey and multiple semi-structured interviews with officials from the Palestinian governmental agriculture related agencies and active non-governmental organizations (NGOs) used for gathering information on wheat and barley production in Palestine. The gathered data along with information and subsequent results prevailed that the West Bank since the 1970s has experienced a significant decrease in winter rainfall. Across 15 sites, growing season rainfall (September to May) decreased by an average of 11% and the sum of rainfall in September and October decreased by 45%. Despite the large decline in rainfall, yields based on the actual weather data did not fall. These results were due to the rainfall changes mainly occurring in September and October, a period when rainfall often is less than crop demand. The study arrived at conclusion based on the study results that climate change variabilities have differential impacts on the yield growth of wheat and barley. However, both rainfed dependent crops are adversely affected by the current climate trends. The yields of barley and wheat are decreasing due to increased temperature and decreased precipitation.
基金the FORECOM project (Forest cover changes in mountainous regions – drivers, trajectories and implications, PSRP 008/2010)supported by a grant from Switzerland through the Swiss contribution to the enlarged European Union
文摘Mountain regions are sensitive to climate changes, which make them good indicators of climate change. The aim of this study is to investigate the spatial and temporal variability of air temperature and precipitation in the Polish Carpathians. This study consists of climatological analyses for the historical period 1851-2010 and future projections for 2021-2100. The results confirm that there has been significant warming of the area and that this warming has been particularly pronounced over the last few decades and will continue in the oncoming years.Climate change is most evident in the foothills;however, these are the highest summits which have experienced the most intensive increases in temperature during the recent period. Precipitation does not demonstrate any substantial trend and has high year-to-year variability. The distribution of the annual temperature contour lines modelled for selected periods provides evidence of the upward shift of vertical climate zones in the Polish Carpathians,which reach approximately 350 meters, on average,what indicates further ecological consequences as ecosystems expand or become extinct and when there are changes in the hydrological cycle.
基金Under the auspices of the National Natural Science Foundation of China (No. 40171001)
文摘This paper researches the ecological sustainability of Zhangjiakou City, Hebei Province, China, using the ecological footprint model. According to the study we find that Zhangjiakou City was in the situation of ecological deficit from 1990 to 2000 and the deficit had the enlarging tendency. In 1990 the per capita ecological footprint was 0.964 and the per capita ecological capacity was 0.5 l 8, thus it can be calculated that the per capita ecological deficit was 4).446. However in 2000, the per capita ecological footprint increased to 1.068, at the same time the per capita eco- logical capacity decreased to 0.471, then the per capita ecological deficit in 2000 was 4).597. Furthermore, this paper studies the ecological sustainability of the city from the changes of the ecological footprint of per 10,000 yuan GDP and the productivity of ecological system. Finally the authors point out the shortage of the model and the way to improve it.
基金This work was supported by National Science Foundation of China (No. 20264001 ), National Science Foundation of Jiangxi Province, Innovation Fund for Technology Based Firms of China (No. 06C26213601342).
文摘A series of Poly(arly ether sulfone ether ketone)s containing pendant methyl groups were synthesized by the reaction of 4,4'-[sulfonylbis (1,4-phenylene)dioxy] dibenzoyl chloride (SODBC) with 4,4'- diphenoxy diphenylsulfone (DPODPS), 4,4'- di(2-methylphenoxy) diphenylsulfone (o-Me-DPODPS), 4,4'- di(3-methylphenoxy) diphenylsulfone (m-Me-DPODPS), 4,4'- di (2,6-bimethylphenoxy) biphenylsulfone(o-Me2-DPODPS) respectively, in a mixture of 1,2-dichloroethane (DCE) and N-methylpyrrolidone (NMP). These reactions were catalyzed by anhydrous aluminum chloride (AlCl). The characteristic of copolymers were studied by means of advanced analytical techniques such as FT-IR,1H-NMR, DSC, TGA and WAXD. The results show glass transition temperature (Tg) in the range of 193-206℃, thermally stable in excess of 434℃ and excellent solubility in polar solvents. Methyl-substituted Poly(aryl ether sulfone ketone)s had higher glass transition temperatures, lower initial decomposition temperatures than the unsubstituted ones.
文摘Global changes, including the rise of the sea level and frequent terrible disasters, are apparently threatening the living environment. For environmental mitigation, security, and sustainability, Taiwan should have reliable, incorporative area-based security-information networks to protect their environments. Plural (dual) surveillance which is rooted in biologic senses, e.g., from two-eyes, can have the feature of fault-tolerance, availability and maintainability in monitoring tasks. Further, it can fit the contemporary wireless communication methods being incorporated with MIMO (multi-in multi-out), to prevent information loss, interference, unexpected changes caused by such as clogged water and chemical reactions. Consequently, network prototypes, including SW (spider-web)network and CCC (cube-connected cycle), are proactively suggested. More reliable capabilities, including those encouraging local ferries and drones, for efficient logistic operation and mixed-use buildings with quality assured performance, can be good for smart urban growth, resource utilization in Taiwan, which is aimed as an aerotropolis--a means for placemaking.
基金Project supported by the Foundation for the Key Disciplines of Nanjing University of Technology.
文摘Xiashu loess strata are widely distributed along the middle-lower reaches of the Yangtze River in East China with the stratum near Nanjing,Jiangsu Province being typical.The cyclic variability of the stratum was investigated through comparison of geological features,chemical composition,and swelling-shrinkage properties between the loess and the paleosol layers.Based on the investigation of such a cyclic variability,soil behavior associated with the unsaturated state of the Xiashu loess stratum and its usefulness for geotechnical design and construction in the Nanjing area was analyzed. The stratum consisted of two types of cyclically alternating soil layers,namely the loess and the paleosol layers,which was the major cause for its cyclic variability.The loess and the paleosol layers were formed in different sedimentary environments.In order to avoid detrimental results from the differential engineering properties between them,this study suggested for the practitioners the importance of inspecting the variation of water content and controlling the downward net fluxes during geotechnical construction in the Nanjing area.
基金Under the auspices of National Natural Science Foundation of China (No. 40925003, 40930528, 40801041)
文摘Severe water erosion is notorious for its harmful effects on land-water resources as well as local societies. The scale effects of water erosion, however, greatly exacerbate the difficulties of accurate erosion evaluation and hazard control in the real world. Analyzing the related scale issues is thus urgent for a better understanding of erosion variations as well as reducing such erosion. In this review article, water erosion dynamics across three spatial scales including plot, watershed, and regional scales were selected and discussed. For the study purposes and objectives, the advantages and disadvantages of these scales all demonstrate clear spatial-scale dependence. Plot scale studies are primarily focused on abundant data collection and mechanism discrimination of erosion generation, while watershed scale studies provide valuable information for watershed management and hazard control as well as the development of quantitatively distributed models. Regional studies concentrate more on large-scale erosion assessment, and serve policymakers and stakeholders in achieving the basis for regulatory policy for comprehensive land uses. The results of this study show that the driving forces and mechanisms of water erosion variations among the scales are quite different. As a result, several major aspects contributing to variations in water erosion across the scales are stressed: differences in the methodologies across various scales, different sink-source roles on water erosion processes, and diverse climatic zones and morphological regions. This variability becomes more complex in the context of accelerated global change. The changing climatic factors and earth surface features are considered the fourth key reason responsible for the increased variability of water erosion across spatial scales.
基金Project(51275024)supported by the National Natural Science Foundations of ChinaProject(2015M580037)supported by China’s Postdoctoral Science FundingProjects(XJ2015002,G-YZ90)supported by Hong Kong Scholars Program Foundations,China
文摘The radial deformation design of turbine disk seriously influences the control of gas turbine high pressure turbine(HPT) blade-tip radial running clearance(BTRRC). To improve the design of BTRRC under continuous operation, the nonlinear dynamic reliability optimization of disk radial deformation was implemented based on extremum response surface method(ERSM), including ERSM-based quadratic function(QF-ERSM) and ERSM-based support vector machine of regression(SR-ERSM). The mathematical models of the two methods were established and the framework of reliability-based dynamic design optimization was developed. The numerical experiments demonstrate that the proposed optimization methods have the promising potential in reducing additional design samples and improving computational efficiency with acceptable precision, in which the SR-ERSM emerges more obviously. Through the case study, we find that disk radial deformation is reduced by about 6.5×10–5 m; δ=1.31×10–3 m is optimal for turbine disk radial deformation design and the proposed methods are verified again. The presented efforts provide an effective optimization method for the nonlinear transient design of motion structures for further research, and enrich mechanical reliability design theory.
文摘The Igbo language has grown and developed to what is known as Standard Igbo (Igbo Izugbe) today. Series of efforts have gone into the modification and invention of words to ensure wider acceptability and intelligibility While this is a welcome idea, the tendency of the loss of communal identity in terms of the original local variety of the Igbo Language spoken by each community becomes very obvious. As Igbos can easily distinguish an Anambra man from an Imo man, it is also necessary that within Arlambra, one should be able to locate a particular town in the area through the spoken Igbo Language variety. This paper studies some of these local variants and advocates for a method of preserving such rich cultural heritage which are so valuable for posterity
文摘Athens, a metropolis characterized by agglutination and compactness, but at the same time facing numerous urban and transport issues, saw its population swell during the 20th century which led to extensive urbanization phenomena. This continued urbanization increases profoundly all urban activities with transportation being the key driver in energy consumption. Theories for sustainable cities prerequisite are the integration of a number of acts in order to reduce energy consumption, with mobility being the first consideration among others. The aim of this paper is to critically explore implemented policies and plans as well as forthcoming strategic plans in terms of sustainable mobility as imposed in large scale regeneration plans in contemporary Athens. Research focuses on strategic interventions since the 1980s, such as the Athenian Daktylios (ring road for circulation management) and its later adjustments, the upcoming pedestrianization and unification of the commercial triangle and its subsequent tram line extension as well as the notable implementation of the metropolitan cycling network. Moreover, the discussion takes into consideration the implications of the Greek economic crisis in mobility choices, as aimless travels have been reduced to a minimum, several cars have been abandoned and cyclists seem to tentatively claim some space in the urban environment. What will likely be the next day in the Athenian historic centre? Considering the transformations that are expected in the immediate future, this research paper explores their potential to enhance urban environment, reduce climate change impacts and amplify resilience.
文摘This study aimed at the physical, chemical and biochemical changes during ripening of Sweetsop (Annona squamosa L.) and Golden Apple (Spondias citherea Sonner) fruits during ripening as important features to better understand their postharvest handling. It was carried out physical analysis such as firmness and chemical analysis such as total chlorophyll, total carotenoids, soluble solids, pectins and titrable acidity and biochemical analysis such as pectin methyl esterase, polygalacturonase, cellulase, and peroxidase and polyphenoloxidase activities in crude extract. Fruits were harvested at different stages of ripening. Experimental design was completely randomized and was carried out analysis of variance and Tukey tests, Total chlorophyll was decreasing in later stages of ripening, total soluble solid contents increased as the fruits ripen, while the acidity expressed percentage of citric acid decreased during fruits ripening. The loss of firmness and soluble solids content increased as the fruit get ripped stage, while the content of pectin decreased. Activity was observed for pectin methyl esterase and polygalacturonase enzymes during all stages of maturation, presenting the highest activity for both enzymes in the mature state. No cellulase activity detected at any stage during the ripening of these fruits. Activity of the enzyme polyphenoloxidase and peroxidase, associated with pulp browning was higher in the last stages of ripening of these fruits. Physical, chemical and biochemical patterns during ripening were different according to fruit species suggesting differential postharvest handling requirements.
文摘The processes of nutrient depletion and soil degradation within smallholder farms of central Kenya are spatially heterogeneous, determined by both biophysical and socio-economic factors. A monitoring study involving nutrient stocks, flows and balances was conducted in central Kenya to explore between and within-farm variability in soil fertility management and identify spatial niches for targeting soil fertility management strategies. Focus group discussions were conducted and farms grouped into 3 farm types (rich, medium and poor). Nine case-study farms - three from each of the farm types - were randomly selected from the 50 farms studied, for detailed resource flow mapping. The farms were visited to record movement of nutrients inputs using a monitoring protocol covering soil, crops, livestock, and socio-economic aspects of the farm. Soil in different plots were sampled at a depth of 0-20 cm and analyzed for texture, pH, C, N, available P, exchangeable K+, Mg2+ and Ca2+. Results revealed that wealthy farmers added an average of 51.3 kg/ha N, 37 kg/ha P, and 244 kg/ha K, compared to 25.9 kg/ha N, 14.5 kg/ha P and 50.7 kg/ha K for the poor farmers. In all farm types, home fields received more nutrient inputs compared to the outfields. Consequently, maize grain yields, partial nutrient balances and soil nutrient stocks were significantly higher in wealthy farms and home fields compared to poor farms and outfields, respectively. These results imply that different soil management strategies are required to achieve similar yields on the different field and farm types and avert soil degradation.
文摘Lake Vrana on the island of Cres is one of the largest fresh water features on Mediterranean islands. The maximum depth of the lake is 72 m and it stores 220 million m3 of fresh water. The paper provides an overview of lake and groundwater temperature measurements to date and recent activities within the EU project "CC-WaterS (Climate Change and Impacts on Water Supply)". Groundwater temperatures in the lake surrounding are almost constant throughout the year, in the range from 14.6 ℃ to 13.1 ℃, while thermodynamic cycle of the lake conforms to the characteristics of a monomictic, medium depth lake in the moderate climate belt. Present and future climate simulations using three limited area models were analyzed (Aladin, Promes and RegCM3), they pointed out further air temperature increase in range of 0.27 ℃/10 yrs to 0.32 ℃/10 yrs. The significant changes of precipitation rates were not indicated. Considering increasing water consumption from the lake, already asserted negative trends, indicated climate changes and possible effects on the lake recharge, it is necessary to establish continual monitoring of parameters that describe lake system behaviour and periodically analyze lake conditions, especially with respect to the extraction for the public water supply.
文摘The most important achievement in the Paris Agreement is to set up emission reduction target by commitment submitted by each country/ region with the form INDC. However the emission reduction target inside INDCs could not match with the emission pathway for the global to keep a global temperature rise this century well below 2 ℃ and to drive efforts to limit the temperature increase even further to 1.5 ℃ above pre- industrial levels. It is important for countries to do more than their commitment in INDCs, especially in near term. This paper looks at the near term trend for possibilities for further emission reduction compared with INDCs, and found there do have the possibility. It concludes there is space for the four countries/regions to do more than their INDCs submitted to UNFCCC, and see the light towards to a global 2 ℃ target.