In order to resolve the issue of soil erosion in East African plateau, a micro-landscape irrigation region was established in Ethiopia plateau to research status quo of agricultural demonstration site in Jari in Ethio...In order to resolve the issue of soil erosion in East African plateau, a micro-landscape irrigation region was established in Ethiopia plateau to research status quo of agricultural demonstration site in Jari in Ethiopia and to analyze the relation between structure and function of inner elements in different landscapes of demonstration site. Furthermore, in accordance with ecology, silviculture, agriculture and economics, the ecological landscapes were classified as per landscape functions; lands returning from farming were classified and re-used; ecosystems of grassland, river, agriculture and courtyard were researched; the feasibility of ecological restoration and sustainable development in demonstration site was demonstrated; the model for rational irrigation and water conservation was proposed. The research guarantees sustainable development of agriculture and animal husbandry and provides references for undeveloped countries with similar problems.展开更多
Significant quantities of slag are generated as waste material or by-product every day from steel industries. They usually contain considerable quantities of valuable metals and materials. Transforming these solid was...Significant quantities of slag are generated as waste material or by-product every day from steel industries. They usually contain considerable quantities of valuable metals and materials. Transforming these solid wastes from one form to another to be reused either by the same production unit or by different industrial installation is very much essential not only for conserving metals and mineral resources but also for protecting the environment. The sustainable development concept requires a more efficient management of waste materials and preservation of environment. The paper presents the basic characteristics of slag, analyses and it's modification by incorporating some essential plant nutrients and the possibility of its application as fertilizer was studied.展开更多
Current methods that utilize simple data or models to judge whether soil fertility can selfdevelop are not sufficiently rigorous. A new framework has been set up using catastrophe theory, laboratory experiment, field ...Current methods that utilize simple data or models to judge whether soil fertility can selfdevelop are not sufficiently rigorous. A new framework has been set up using catastrophe theory, laboratory experiment, field work, and 3S(Geographic information system, Global positioning system, and Remote sensing) to explore soil fertility catastrophe under ecological restoration, discriminate whether soil fertility can self-develop, and propose adjustment of ecological restoration measures in the Zhuxi watershed of Changting County, Fujian Province, China, which is a typical representative of the red soil hilly region of China. The results show that: 1) the soil fertility is obviously improved through the four ecological restoration measures, which impels soil fertility catastrophe. Among 89 soil samples, catastrophic soil samples and stable soil samples account for 26(29.21%) and 63(70.79%) of the samples, respectively. The four ecological restoration measures are listed in the order lowquality forest improvement > arbor–bush–herb mixed plantation > orchard improvement > closing measures according to the proportions of catastrophic soil samples. A typical soil sample in Bashilihe that can self-develop is selected as the criterion to judge the upper lobe and lower lobe of soil fertility in the process surface of the Cusp catastrophe model. Twenty-six(29.21%) were in the middle lobe, 10(11.24%) were in the upper lobe, and 53(70.79%) were in the lower lobe. The catastrophic direction of 26 catastrophic soil samples is to the upper lobe according to soil and water loss change as well as fieldwork. There is a significant positive correlation of Δ with soil and water loss change, and the lower soil and water loss relates to higher catastrophic probability. 2) Soil fertility self-development could be regionalized as "Soil fertility can self-develop" whose area was 12.74 km2(28.33%) distributed mainly in the leftmost and rightmost parts, "Soil fertility tends to self-develop" whose area was 11.63 km2(25.89%) distributed mainly in the middle part, and "Soil fertility cannot self-develop" whose area was 20.58 km2(45.78%) distributed mainly between the above two types. 3) There is no need to take ecological restoration measures and excessive human interference should be avoided in the future in regions of "Soil fertility can self-develop" and "Soil fertility tends to self-develop," and ecological restoration measures should be taken in region of "Soil fertility cannot self-develop." 4) We suggest withdrawal and implementation of ecological restoration measures should be incorporated into the evaluation criteria of ecological restoration to avoid misuse of funds.展开更多
The geographical location makes the port of Livorno one of the most important in Italy. The port, in fact, benefits of an extended network of roads and rails connecting it with the rest of Italy, and central and south...The geographical location makes the port of Livorno one of the most important in Italy. The port, in fact, benefits of an extended network of roads and rails connecting it with the rest of Italy, and central and southern Europe as well. The history of Livorno and its port is inextricably linked to that of Pisa and Florence, and to the complexity of events that determined the political set-up of the region along several centuries. Looking at the new port plan of Livorno has made it necessary an extensive overview of the history of both the port, and of its planning. This analysis has allowed: to understand the reason for the different choices made in the past for the development of the port, highlighting, when necessary, the errors made; to identify the strengths and weaknesses of the existing port infrastructure; to identify the works needed to boost the port in the European context. The purpose of this paper is to provide a summary of the analysis performed for the implementation of the new Livorno port plan 2010 and show how the port planning in Italy is often conditioned by hundreds of centuries of history.展开更多
Studies about the elderly are mostly focused on morbidity and psychological conditions of the elderly. Effects of social relations have been noted to be important for the well-being of an elderly person. Later studies...Studies about the elderly are mostly focused on morbidity and psychological conditions of the elderly. Effects of social relations have been noted to be important for the well-being of an elderly person. Later studies have begun to look at socioeconomic status of the elderly to see its relation to the level of morbidity. This paper is based on a nationwide survey. A total of 10 percent of elderly total population was interviewed to obtain socioeconomic and lifestyle information. A self reporting method was used as it was easiest to obtain the answers from the elderly. A total of 1410 elderly respondents aged 60 and above were interviewed from the regions of northern, eastern, middle and southern Peninsular Malaysia and also from Sabah and Sarawak. The data was analyzed using the SPSS 16. Quantitative analysis based on mean, standard deviation and multiple regressions was done. Findings show that higher morbidity rate lowers ones economic well-being. Females report higher morbidity then males, while those who are married and residing in rural area also reoort lower morbidity.展开更多
In this paper, the complexity of intra coding is first analyzed so as to achieve a weight of complexity measurement for each intra mode. Then, a new complexity scalable control algorithm for intra coding in H. 264 is ...In this paper, the complexity of intra coding is first analyzed so as to achieve a weight of complexity measurement for each intra mode. Then, a new complexity scalable control algorithm for intra coding in H. 264 is proposed, based on the rearrangement of the order of candidate modes and an efficient complexity allocation and control (CAAC) scheme at the macroblock (MB) level. The candidate modes of each MB are rearranged according to the local-edge information. Experimental results show that our proposed algorithm can make an appropriate cut-off point of the candidate modes sequence adaptively according to the current energy condition of a mobile device, so as to adjust the complexity at any level while maximizing the video quality, which can prolong the operational lifetime of the battery with minimum degradation in video quality.展开更多
With the increasing growing of the environmental issues and climatic change, sustainable urban development of cities became an urgent demand. Urban development relied on four pillars; the institutional, social, enviro...With the increasing growing of the environmental issues and climatic change, sustainable urban development of cities became an urgent demand. Urban development relied on four pillars; the institutional, social, environmental and economic pillars. Urban regeneration is not a single concept; it is a group of strategies. This study concluded that those strategies include; the public action, certification programs and corporate responsibility theories.展开更多
CD4^+CD25^+ Regulatory T cells (Treg) have been found to down-regulate immune activation in HIV-1 infection. However, whether the depletion of Treg benefits to the disease status of HIV infection remains undefined...CD4^+CD25^+ Regulatory T cells (Treg) have been found to down-regulate immune activation in HIV-1 infection. However, whether the depletion of Treg benefits to the disease status of HIV infection remains undefined. To address this issue, we enumerated the Treg absolute counts and frequency in 75 antiviral-naive HIV-1-infected individuals in this study. It was found that HIV-infected patients displayed a significant decline in Treg absolute counts but a significant increase in Treg frequency. In addition, with disease progression indicated by CD4 T-cell absolute counts, circulating Treg frequency gradually increased; while Treg absolute counts were gradually decreased, suggesting that the alteration of Treg number closely correlated with disease progression in HIV infection Functional analysis further showed that Treg efficiently inhibit both CD4 and CD8 T cell proliferation in vitro. Thus, our findings indicates that Treg actively participate in pathogenesis of chronic HIV infection, influencing the disease progression.展开更多
Nanocellulose composites combine the advantages of nanocellulose and composites. Recently, nanocellulose composites have been received more attentions due to their improved properties and promising broad applications....Nanocellulose composites combine the advantages of nanocellulose and composites. Recently, nanocellulose composites have been received more attentions due to their improved properties and promising broad applications. In the past, rapid progress has been made in the synthesis, properties, and mechanism of nanocellulose composites and potential applications were reported. There are a few reports on the increasing applications of nanocellulose composites with focus on the biomedical field, environmental field, electrode and sensor applications. In this article, the recent development of nanocellulose composites was reviewed via some typical examples. In addition to the synthesis methods, improved properties and potential applications were discussed. The problems and future applications of nanocellulose composites were also suggested.展开更多
This study estimates the environmental and socioeconomic impacts of coffee production in the agroforestry system in the settlements of farmers located in the West of the state of Silo Paulo, Brazil, in the region know...This study estimates the environmental and socioeconomic impacts of coffee production in the agroforestry system in the settlements of farmers located in the West of the state of Silo Paulo, Brazil, in the region known as Pontal of Paranapanema, aiming at the development of programs to support the growth of production sustainable coffee and programs to protect the coffee activity before the possible global climate change. The settlements are located in areas with sandy soils and highly degraded by human action Moreover, the region is considered marginal for the production of coffee, because it is subject to periods of high temperatures, prolonged drought and frost risk, which hinders the sustainability of farms. The environmental and socioeconomic impacts of agroforestry are analyzed through Ambitec-agro system, consisting of a set of indicators aimed at ex-post evaluation of the contribution of technological innovation to environmental, social and economic development of an agricultural activity. The system Ambitec involves: (1) general data collection about the technology; (2) application of questionnaires with adopters selected and insertion of data on impact indicators spreadsheets via platform MS-Excel and to obtain quantitative results and impacts partial indexes and aggregates the impact of technology selected; (3) analysis and interpretation of indices obtained, which vary between -15 and 15. The results indicate that agroforestry management can contribute to: (1) maintaining or increasing the sustainability of traditional coffee-growing regions in the case of sudden climate change; (2) the expansion of the coffee regions now considered unsuitable for the cultivation of coffee; (3) for sustainable regional development.展开更多
Tikhonov regularization is a powerful tool for solving linear discrete ill-posed problems.However,effective methods for dealing with large-scale ill-posed problems are still lacking.The Kaczmarz method is an effective...Tikhonov regularization is a powerful tool for solving linear discrete ill-posed problems.However,effective methods for dealing with large-scale ill-posed problems are still lacking.The Kaczmarz method is an effective iterative projection algorithm for solving large linear equations due to its simplicity.We propose a regularized randomized extended Kaczmarz(RREK)algorithm for solving large discrete ill-posed problems via combining the Tikhonov regularization and the randomized Kaczmarz method.The convergence of the algorithm is proved.Numerical experiments illustrate that the proposed algorithm has higher accuracy and better image restoration quality compared with the existing randomized extended Kaczmarz(REK)method.展开更多
This research was conducted to investigate the ductility behavior of timber beams strengthened with CFRP (carbon fiber reinforced polymer) plates. The surface to be bonded was spiked by punching small holes of 2 mm ...This research was conducted to investigate the ductility behavior of timber beams strengthened with CFRP (carbon fiber reinforced polymer) plates. The surface to be bonded was spiked by punching small holes of 2 mm in diameter with 10 mm spacing. The aim is to increase bonding capacity by having small studs. Five beams with the dimension of 100 mm x 200 mm x 3,000 mm were tested where one of the beams was used as control beam (unstrengthened). The remaining beams were strengthened with different configurations before tested to failure under four-point loading. The results showed that the ductility was increased as the percentage of CFRP increased. The ductility was dramatically improved where the highest ductility index based on deflection method was 2.2 where the percentage increase was 37.5%, whereas the highest ductility index based on energy method was 3.2 where the percentage increase was 88.2%. From this study, it was found that 0.3% is the optimum value of CFRP area to achieve maximum ductility index. Ductility index obtained from energy method gives higher values when compared to deflection method. All beams in this study did not fail due to peel off or debonding. It was also proved that the spikes that have been made at the wood surface were very effective for bonding.展开更多
The interface plays the central role in the failure analysis of composite laminates, therefore, the interface material properties are taken as the independent parameters. A simple, universal and practicable criterion,...The interface plays the central role in the failure analysis of composite laminates, therefore, the interface material properties are taken as the independent parameters. A simple, universal and practicable criterion, i.e. a ratio criterion of strain energy release rate, is proposed to determine the growing direction of a fatigue crack in the composite laminates. The method of arbitrary lines, which is very effective to solve the problems with high gradient feature, is used to analyze the experimental results at the key moments when a crack kinks, turns into the interface, or bifurcates. An approximate method of computing the energy release rate is given. The fatigue fracture tests of composite laminates are carried out, and the numerical predictions of crack growing directions agree well with the experimental results. It is concluded that the methods suggested in this paper are effective to obtain the cracking history and the growing path of a fatigue crack in composite laminates.展开更多
Necessity of land reclamation is discussed, setting out viewpoint of sustainable development and land connotation and its attribute and combining destroyed forms and characteristics of land in coal mining areas. It is...Necessity of land reclamation is discussed, setting out viewpoint of sustainable development and land connotation and its attribute and combining destroyed forms and characteristics of land in coal mining areas. It is pointed out that land reclamation of coal mining areas is basic guarantee of solving contradiction between coal mining areas and countryside,raising life of resident and ensuring regional sustainable development.展开更多
The fatigue crack growth(FCG) mechanism of a cast hybrid metal matrix composite(MMC) reinforced with SiC particles and Al2O3 whiskers was investigated. For comparison, the FCG mechanisms of a cast MMC with Al2O3 whisk...The fatigue crack growth(FCG) mechanism of a cast hybrid metal matrix composite(MMC) reinforced with SiC particles and Al2O3 whiskers was investigated. For comparison, the FCG mechanisms of a cast MMC with Al2O3 whiskers and a cast Al alloy were also investigated. The results show that the FCG mechanism is observed in the near-threshold and stable-crack-growth regions.The hybrid MMC shows a higher threshold stress intensity factor range, ?Kth, than the MMC with Al2O3 and Al alloy, indicating better resistance to crack growth in a lower stress intensity factor range, ?K. In the near-threshold region with decreasing ?K, the two composite materials exhibit similar FCG mechanism that is dominated by debonding of the reinforcement–matrix interface, and followed by void nucleation and coalescence in the Al matrix. At higher ?K in the stable- or mid-crack-growth region, in addition to the debonding of the particle–matrix and whisker–matrix interface caused by cycle-by-cycle crack growth at the interface, the FCG is affected predominantly by striation formation in the Al matrix. Moreover, void nucleation and coalescence in the Al matrix and transgranular fracture of SiC particles and Al2O3 whiskers at high ?K are also observed as the local unstable fracture mechanisms.However, the FCG of the monolithic Al alloy is dominated by void nucleation and coalescence at lower ?K, whereas the FCG at higher ?K is controlled mainly by striation formation in the Al grains, and followed by void nucleation and coalescence in the Si clusters.展开更多
s: The current status of AEE in Hunan Province is introduced in brief. The reasons why the AEE was polluted and destroyed are analyzed; the countermeasures for improving AEE are brought forward.
China has experienced dramatic land use changes over recent decades, with marked environmental and socio-economic consequences. Hengshan County, located in the aeolian-loessial area of Northwest China, was investigate...China has experienced dramatic land use changes over recent decades, with marked environmental and socio-economic consequences. Hengshan County, located in the aeolian-loessial area of Northwest China, was investigated to illustrate land use changes and their implications for environmental and long-term rural economic development. The farmland in Hengshan County significantly decreased during 1990–2003, whereas forest land and grassland increased. The conversion rates of farmland, orchard land, forest land and construction land varied markedly among different periods: 1990–1995, 1995–2000 and 2000–2003. Conversion of orchard land, grassland and construction land was dominant in 1990–1995, whereas the conversion of farmland to forest land mainly occurred in 2000–2003. The results suggested a profound transition in institutional policy and political economy of land management, including implementation of integrated soil erosion control projects, adoption of a market-oriented economy and the ‘Grain-for-Green’ policy, during this period in China. To achieve long-term sustainable land use in Hengshan County, efforts should aim at increasing off-farm income of rural families as well as establishing land-economizing mechanisms to promote land productivity, in addition to conservation measures.展开更多
基金Supported by South-South Cooperation Project of SSC/SPFS-FAO-Ethiopia-China~~
文摘In order to resolve the issue of soil erosion in East African plateau, a micro-landscape irrigation region was established in Ethiopia plateau to research status quo of agricultural demonstration site in Jari in Ethiopia and to analyze the relation between structure and function of inner elements in different landscapes of demonstration site. Furthermore, in accordance with ecology, silviculture, agriculture and economics, the ecological landscapes were classified as per landscape functions; lands returning from farming were classified and re-used; ecosystems of grassland, river, agriculture and courtyard were researched; the feasibility of ecological restoration and sustainable development in demonstration site was demonstrated; the model for rational irrigation and water conservation was proposed. The research guarantees sustainable development of agriculture and animal husbandry and provides references for undeveloped countries with similar problems.
文摘Significant quantities of slag are generated as waste material or by-product every day from steel industries. They usually contain considerable quantities of valuable metals and materials. Transforming these solid wastes from one form to another to be reused either by the same production unit or by different industrial installation is very much essential not only for conserving metals and mineral resources but also for protecting the environment. The sustainable development concept requires a more efficient management of waste materials and preservation of environment. The paper presents the basic characteristics of slag, analyses and it's modification by incorporating some essential plant nutrients and the possibility of its application as fertilizer was studied.
基金funded by the National Natural Science Foundation of China(Grant Nos.41371512,41001170)
文摘Current methods that utilize simple data or models to judge whether soil fertility can selfdevelop are not sufficiently rigorous. A new framework has been set up using catastrophe theory, laboratory experiment, field work, and 3S(Geographic information system, Global positioning system, and Remote sensing) to explore soil fertility catastrophe under ecological restoration, discriminate whether soil fertility can self-develop, and propose adjustment of ecological restoration measures in the Zhuxi watershed of Changting County, Fujian Province, China, which is a typical representative of the red soil hilly region of China. The results show that: 1) the soil fertility is obviously improved through the four ecological restoration measures, which impels soil fertility catastrophe. Among 89 soil samples, catastrophic soil samples and stable soil samples account for 26(29.21%) and 63(70.79%) of the samples, respectively. The four ecological restoration measures are listed in the order lowquality forest improvement > arbor–bush–herb mixed plantation > orchard improvement > closing measures according to the proportions of catastrophic soil samples. A typical soil sample in Bashilihe that can self-develop is selected as the criterion to judge the upper lobe and lower lobe of soil fertility in the process surface of the Cusp catastrophe model. Twenty-six(29.21%) were in the middle lobe, 10(11.24%) were in the upper lobe, and 53(70.79%) were in the lower lobe. The catastrophic direction of 26 catastrophic soil samples is to the upper lobe according to soil and water loss change as well as fieldwork. There is a significant positive correlation of Δ with soil and water loss change, and the lower soil and water loss relates to higher catastrophic probability. 2) Soil fertility self-development could be regionalized as "Soil fertility can self-develop" whose area was 12.74 km2(28.33%) distributed mainly in the leftmost and rightmost parts, "Soil fertility tends to self-develop" whose area was 11.63 km2(25.89%) distributed mainly in the middle part, and "Soil fertility cannot self-develop" whose area was 20.58 km2(45.78%) distributed mainly between the above two types. 3) There is no need to take ecological restoration measures and excessive human interference should be avoided in the future in regions of "Soil fertility can self-develop" and "Soil fertility tends to self-develop," and ecological restoration measures should be taken in region of "Soil fertility cannot self-develop." 4) We suggest withdrawal and implementation of ecological restoration measures should be incorporated into the evaluation criteria of ecological restoration to avoid misuse of funds.
文摘The geographical location makes the port of Livorno one of the most important in Italy. The port, in fact, benefits of an extended network of roads and rails connecting it with the rest of Italy, and central and southern Europe as well. The history of Livorno and its port is inextricably linked to that of Pisa and Florence, and to the complexity of events that determined the political set-up of the region along several centuries. Looking at the new port plan of Livorno has made it necessary an extensive overview of the history of both the port, and of its planning. This analysis has allowed: to understand the reason for the different choices made in the past for the development of the port, highlighting, when necessary, the errors made; to identify the strengths and weaknesses of the existing port infrastructure; to identify the works needed to boost the port in the European context. The purpose of this paper is to provide a summary of the analysis performed for the implementation of the new Livorno port plan 2010 and show how the port planning in Italy is often conditioned by hundreds of centuries of history.
文摘Studies about the elderly are mostly focused on morbidity and psychological conditions of the elderly. Effects of social relations have been noted to be important for the well-being of an elderly person. Later studies have begun to look at socioeconomic status of the elderly to see its relation to the level of morbidity. This paper is based on a nationwide survey. A total of 10 percent of elderly total population was interviewed to obtain socioeconomic and lifestyle information. A self reporting method was used as it was easiest to obtain the answers from the elderly. A total of 1410 elderly respondents aged 60 and above were interviewed from the regions of northern, eastern, middle and southern Peninsular Malaysia and also from Sabah and Sarawak. The data was analyzed using the SPSS 16. Quantitative analysis based on mean, standard deviation and multiple regressions was done. Findings show that higher morbidity rate lowers ones economic well-being. Females report higher morbidity then males, while those who are married and residing in rural area also reoort lower morbidity.
基金Supported by the National High Technology Research and Development Program of China (2008AA01A313 ), the National Natural Science Foundation of China (60772069), and a Grant from the Centre for Signal Processing of the Hang Kong Polytechnic University (1-BB9c).
文摘In this paper, the complexity of intra coding is first analyzed so as to achieve a weight of complexity measurement for each intra mode. Then, a new complexity scalable control algorithm for intra coding in H. 264 is proposed, based on the rearrangement of the order of candidate modes and an efficient complexity allocation and control (CAAC) scheme at the macroblock (MB) level. The candidate modes of each MB are rearranged according to the local-edge information. Experimental results show that our proposed algorithm can make an appropriate cut-off point of the candidate modes sequence adaptively according to the current energy condition of a mobile device, so as to adjust the complexity at any level while maximizing the video quality, which can prolong the operational lifetime of the battery with minimum degradation in video quality.
文摘With the increasing growing of the environmental issues and climatic change, sustainable urban development of cities became an urgent demand. Urban development relied on four pillars; the institutional, social, environmental and economic pillars. Urban regeneration is not a single concept; it is a group of strategies. This study concluded that those strategies include; the public action, certification programs and corporate responsibility theories.
基金The National Outstanding Youth Foundation of China (30525042)National 973 project of China (2006CB504201,2006CB504205)
文摘CD4^+CD25^+ Regulatory T cells (Treg) have been found to down-regulate immune activation in HIV-1 infection. However, whether the depletion of Treg benefits to the disease status of HIV infection remains undefined. To address this issue, we enumerated the Treg absolute counts and frequency in 75 antiviral-naive HIV-1-infected individuals in this study. It was found that HIV-infected patients displayed a significant decline in Treg absolute counts but a significant increase in Treg frequency. In addition, with disease progression indicated by CD4 T-cell absolute counts, circulating Treg frequency gradually increased; while Treg absolute counts were gradually decreased, suggesting that the alteration of Treg number closely correlated with disease progression in HIV infection Functional analysis further showed that Treg efficiently inhibit both CD4 and CD8 T cell proliferation in vitro. Thus, our findings indicates that Treg actively participate in pathogenesis of chronic HIV infection, influencing the disease progression.
基金Financial supported from the Fundamental Research Funds for the Central Universities (No. 2017ZY49)the Foundation (No. KF201607) of Key Laboratory of Pulp and Paper Science and Technology of Ministry of Education/Shandong Province of China
文摘Nanocellulose composites combine the advantages of nanocellulose and composites. Recently, nanocellulose composites have been received more attentions due to their improved properties and promising broad applications. In the past, rapid progress has been made in the synthesis, properties, and mechanism of nanocellulose composites and potential applications were reported. There are a few reports on the increasing applications of nanocellulose composites with focus on the biomedical field, environmental field, electrode and sensor applications. In this article, the recent development of nanocellulose composites was reviewed via some typical examples. In addition to the synthesis methods, improved properties and potential applications were discussed. The problems and future applications of nanocellulose composites were also suggested.
文摘This study estimates the environmental and socioeconomic impacts of coffee production in the agroforestry system in the settlements of farmers located in the West of the state of Silo Paulo, Brazil, in the region known as Pontal of Paranapanema, aiming at the development of programs to support the growth of production sustainable coffee and programs to protect the coffee activity before the possible global climate change. The settlements are located in areas with sandy soils and highly degraded by human action Moreover, the region is considered marginal for the production of coffee, because it is subject to periods of high temperatures, prolonged drought and frost risk, which hinders the sustainability of farms. The environmental and socioeconomic impacts of agroforestry are analyzed through Ambitec-agro system, consisting of a set of indicators aimed at ex-post evaluation of the contribution of technological innovation to environmental, social and economic development of an agricultural activity. The system Ambitec involves: (1) general data collection about the technology; (2) application of questionnaires with adopters selected and insertion of data on impact indicators spreadsheets via platform MS-Excel and to obtain quantitative results and impacts partial indexes and aggregates the impact of technology selected; (3) analysis and interpretation of indices obtained, which vary between -15 and 15. The results indicate that agroforestry management can contribute to: (1) maintaining or increasing the sustainability of traditional coffee-growing regions in the case of sudden climate change; (2) the expansion of the coffee regions now considered unsuitable for the cultivation of coffee; (3) for sustainable regional development.
基金supported by the National Natural Science Foundations of China(Nos.11571171,62073161,and 61473148)。
文摘Tikhonov regularization is a powerful tool for solving linear discrete ill-posed problems.However,effective methods for dealing with large-scale ill-posed problems are still lacking.The Kaczmarz method is an effective iterative projection algorithm for solving large linear equations due to its simplicity.We propose a regularized randomized extended Kaczmarz(RREK)algorithm for solving large discrete ill-posed problems via combining the Tikhonov regularization and the randomized Kaczmarz method.The convergence of the algorithm is proved.Numerical experiments illustrate that the proposed algorithm has higher accuracy and better image restoration quality compared with the existing randomized extended Kaczmarz(REK)method.
文摘This research was conducted to investigate the ductility behavior of timber beams strengthened with CFRP (carbon fiber reinforced polymer) plates. The surface to be bonded was spiked by punching small holes of 2 mm in diameter with 10 mm spacing. The aim is to increase bonding capacity by having small studs. Five beams with the dimension of 100 mm x 200 mm x 3,000 mm were tested where one of the beams was used as control beam (unstrengthened). The remaining beams were strengthened with different configurations before tested to failure under four-point loading. The results showed that the ductility was increased as the percentage of CFRP increased. The ductility was dramatically improved where the highest ductility index based on deflection method was 2.2 where the percentage increase was 37.5%, whereas the highest ductility index based on energy method was 3.2 where the percentage increase was 88.2%. From this study, it was found that 0.3% is the optimum value of CFRP area to achieve maximum ductility index. Ductility index obtained from energy method gives higher values when compared to deflection method. All beams in this study did not fail due to peel off or debonding. It was also proved that the spikes that have been made at the wood surface were very effective for bonding.
文摘The interface plays the central role in the failure analysis of composite laminates, therefore, the interface material properties are taken as the independent parameters. A simple, universal and practicable criterion, i.e. a ratio criterion of strain energy release rate, is proposed to determine the growing direction of a fatigue crack in the composite laminates. The method of arbitrary lines, which is very effective to solve the problems with high gradient feature, is used to analyze the experimental results at the key moments when a crack kinks, turns into the interface, or bifurcates. An approximate method of computing the energy release rate is given. The fatigue fracture tests of composite laminates are carried out, and the numerical predictions of crack growing directions agree well with the experimental results. It is concluded that the methods suggested in this paper are effective to obtain the cracking history and the growing path of a fatigue crack in composite laminates.
文摘Necessity of land reclamation is discussed, setting out viewpoint of sustainable development and land connotation and its attribute and combining destroyed forms and characteristics of land in coal mining areas. It is pointed out that land reclamation of coal mining areas is basic guarantee of solving contradiction between coal mining areas and countryside,raising life of resident and ensuring regional sustainable development.
基金the Ministry of Education, Science, Sports and Culture of the Government of Japan for providing financial support during this research work
文摘The fatigue crack growth(FCG) mechanism of a cast hybrid metal matrix composite(MMC) reinforced with SiC particles and Al2O3 whiskers was investigated. For comparison, the FCG mechanisms of a cast MMC with Al2O3 whiskers and a cast Al alloy were also investigated. The results show that the FCG mechanism is observed in the near-threshold and stable-crack-growth regions.The hybrid MMC shows a higher threshold stress intensity factor range, ?Kth, than the MMC with Al2O3 and Al alloy, indicating better resistance to crack growth in a lower stress intensity factor range, ?K. In the near-threshold region with decreasing ?K, the two composite materials exhibit similar FCG mechanism that is dominated by debonding of the reinforcement–matrix interface, and followed by void nucleation and coalescence in the Al matrix. At higher ?K in the stable- or mid-crack-growth region, in addition to the debonding of the particle–matrix and whisker–matrix interface caused by cycle-by-cycle crack growth at the interface, the FCG is affected predominantly by striation formation in the Al matrix. Moreover, void nucleation and coalescence in the Al matrix and transgranular fracture of SiC particles and Al2O3 whiskers at high ?K are also observed as the local unstable fracture mechanisms.However, the FCG of the monolithic Al alloy is dominated by void nucleation and coalescence at lower ?K, whereas the FCG at higher ?K is controlled mainly by striation formation in the Al grains, and followed by void nucleation and coalescence in the Si clusters.
文摘s: The current status of AEE in Hunan Province is introduced in brief. The reasons why the AEE was polluted and destroyed are analyzed; the countermeasures for improving AEE are brought forward.
基金Project supported by the Open Fund of Key Laboratory of Land Use, Ministry of Land & Resources of China the National Natural Science Foundation of China (Nos.40871257 and 40635029).
文摘China has experienced dramatic land use changes over recent decades, with marked environmental and socio-economic consequences. Hengshan County, located in the aeolian-loessial area of Northwest China, was investigated to illustrate land use changes and their implications for environmental and long-term rural economic development. The farmland in Hengshan County significantly decreased during 1990–2003, whereas forest land and grassland increased. The conversion rates of farmland, orchard land, forest land and construction land varied markedly among different periods: 1990–1995, 1995–2000 and 2000–2003. Conversion of orchard land, grassland and construction land was dominant in 1990–1995, whereas the conversion of farmland to forest land mainly occurred in 2000–2003. The results suggested a profound transition in institutional policy and political economy of land management, including implementation of integrated soil erosion control projects, adoption of a market-oriented economy and the ‘Grain-for-Green’ policy, during this period in China. To achieve long-term sustainable land use in Hengshan County, efforts should aim at increasing off-farm income of rural families as well as establishing land-economizing mechanisms to promote land productivity, in addition to conservation measures.