[Objective] This study aimed to understand and grasp the soil heavy metal pollution status of agricultural habitat environment in Xi＇an City. [Method] The soil heavy metal pollution status of pollution-free agricultu...[Objective] This study aimed to understand and grasp the soil heavy metal pollution status of agricultural habitat environment in Xi＇an City. [Method] The soil heavy metal pollution status of pollution-free agricultural products-producing areas in 9 counties （districts） of Xi＇an City was investigated. A total of 609 soil samples were collected, and their Cd, Hg, As, Pb and Cr contents were determined. In addition, the heavy metal pollution status of the collected soil samples was evaluated by Nemerow index method. [Result] The pollution in Baqiao, Chang＇an; Gaoling, Lan- tian, Lintong and Yanliang was of grade I, belonging to clean level; the pollution in Hu County, Weiyang and Zhouzhi was of grade II, near the warning line, belong to relatively clean level. There was no large-area soil heavy metal pollution overall. The investigated areas could be used as production bases of pollution-free agricultural products and even high-quality agricultural products. However, the heavy met- als contents in some individual areas exceeded relevant soil environmental quality standards, and they should be avoided or forbidden during regional planning and selection of production area. [Conclusion] Soil heavy metal pollution of agricultural habitat environment in Xi＇an City is generally at good status. Targeting at the future development plan of Xi＇an City, feasible and scientific suggestions are put forward.展开更多
A new technique of dimension reduction named projection pursuit is applied to model and evaluatewetland soil quality variations in the Sanjiang Plain, Helongjiang Province, China. By adopting the im-proved real-coded ...A new technique of dimension reduction named projection pursuit is applied to model and evaluatewetland soil quality variations in the Sanjiang Plain, Helongjiang Province, China. By adopting the im-proved real-coded accelerating genetic algorithm (RAGA), the projection direction is optimized and multi-dimensional indexes are converted into low-dimensional space. Classification of wetland soils and evaluationof wetland soil quality variations are realized by pursuing optimum projection direction and projection func-tion value. Therefore, by adopting this new method, any possible human interference can be avoided andsound results can be achieved in researching quality changes and classification of wetland soils.展开更多
Stability condition and quality evaluation formula of layerlike backfilling roof,Q≥C,where Q denotes is quality index depending on allowable compressive or tensile strength and integrity of backfilling,and C is the t...Stability condition and quality evaluation formula of layerlike backfilling roof,Q≥C,where Q denotes is quality index depending on allowable compressive or tensile strength and integrity of backfilling,and C is the technical index depending on mining method and backfilling technology,were inferred according to simply supported beam theorem.Technical treatment measures for instable backfilling roof,including optimum of appropriate filling materials and dosage for excellent flow property and reduction of backfill cost.It is proved that slope equation of backfill slurry in a stope to be filled is y=hexp[x2/(2σ)2)],where h is height of cone and σ2 is mean square,and that optimum drainage point of backfill slurry can be determined by the equation and sizes of stope.Case study indicates that the results can give a theoretical support for quality evaluation and control of layerlike backfilling.展开更多
Fuzzy association rules (FARs) can be powerful in assessing regional soil quality, a critical step prior to land planning and utilization; however, traditional FARs mined from soil quality database, ignoring the impor...Fuzzy association rules (FARs) can be powerful in assessing regional soil quality, a critical step prior to land planning and utilization; however, traditional FARs mined from soil quality database, ignoring the importance variability of the rules, can be redundant and far from optimal. In this study, we developed a method applying different weights to traditional FARs to improve accuracy of soil quality assessment. After the FARs for soil quality assessment were mined, redundant rules were eliminated according to whether the rules were significant or not in reducing the complexity of the soil quality assessment models and in improving the comprehensibility of FARs. The global weights, each representing the importance of a FAR in soil quality assessment, were then introduced and refined using a gradient descent optimization method. This method was applied to the assessment of soil resources conditions in Guangdong Province, China. The new approach had an accuracy of 87%, when 15 rules were mined, as compared with 76% from the traditional approach. The accuracy increased to 96% when 32 rules were mined, in contrast to 88% from the traditional approach. These results demonstrated an improved comprehensibility of FARs and a high accuracy of the proposed method.展开更多
Wetland soil quality degradation caused by large-scale agricultural reclamation on the Sanjiang Plain of Northeast China has been widely reported. A relative soil quality evaluation (RSQE) model and a projection pursu...Wetland soil quality degradation caused by large-scale agricultural reclamation on the Sanjiang Plain of Northeast China has been widely reported. A relative soil quality evaluation (RSQE) model and a projection pursuit evaluation (PPE) model based on real-coded accelerating genetic algorithm were introduced to evaluate quality variations in top layers of the main wetland soils on the Sanjiang Plain in 1999 and 2003, respectively. As soil quality degradation boundaries were vague, this study established two fuzzy synthetic evaluation (FSE) models based on the original data and criteria used in the RSQE and PPE models. The outputs of the two FSE models were obtained by choosing two fuzzy composite operators M(∧, ∨) and M(·, ⊕). Statistical analysis showed that the results of the FSE, RSQE, and PPE models were correlated. In particular, outputs of the FSE model using M(·, ⊕) were significantly correlated with those of the RSQE model with r = 0.989 at P < 0.01. Compared with RSQE and PPE models, the FSE model may be more objective in showing soil quality variations and was closer to the natural situation, showing the feasibility and applicability of the FSE model in evaluating soil quality degradation. However, the choice of composite operator was of critical importance. The study of wetland soil quality degradation on the Sanjiang Plain was of scientific and practical significance for protection and management of soils and for sustainable development of agriculture in this area in the future.展开更多
The objective of this work is to obtain the seismic safety coefficient and fracture surface and proceed with the seismic safety evaluation for the rock mass or soil mass surrounding a tunnel,and the limitation of eval...The objective of this work is to obtain the seismic safety coefficient and fracture surface and proceed with the seismic safety evaluation for the rock mass or soil mass surrounding a tunnel,and the limitation of evaluating seismic stability is considered using the pseudo-static strength reduction.By using the finite element software ANSYS and the strength reduction method,new methods of seismic safety evaluation for the rock mass or soil mass surrounding a tunnel are put forward,such as the dynamic finite element static shear strength reduction method and dynamic finite element shear strength reduction method.In order to prove the feasibility of the proposed methods,the results of numerical examples are compared with that of the pseudo-static strength reduction method.The results show that 1) the two methods are both feasible,and the plastic zone first appears near the bottom corners; 2) the safety factor of new method Ⅱ is smaller than that of new method I but generally,and the difference is very small.Therefore,in order to ensure the safety of the structure,two new methods are proposed to evaluate the seismic stability of the rock mass or soil mass surrounding a tunnel.A theoretical basis is provided for the seismic stability of the rock mass or soil mass and the lining surrounding a tunnel and also provided for the engineering application.展开更多
The study aimed to evaluate soil quality using microarthopods density, diversity and soil biological quality index （QBS-ar） under different land use systems and elevation gradients. A secondary aim was to determine ...The study aimed to evaluate soil quality using microarthopods density, diversity and soil biological quality index （QBS-ar） under different land use systems and elevation gradients. A secondary aim was to determine the relationship among soil biological and physiochemical indicators. Three groups of soil microarthropods were recognized viz. （1） Collembola （38%） （2） Acarina （33%） and （3） other microarthropods （29%）. ANOVA indicated that total microarthropods densities differed significantly with land use and elevation. Population density of Acarina and other mieroarthropods were weakly significant different according to land use, while Collembola and Acarina densities showed highly significant difference with elevation. Total microarthropods, Acarina and Collembola densities were positively significantly correlated with soil organic carbon （SOC） and moisture but negatively correlated with bulk density, pH and temperature of the soil. SOC and soil moisture appeared to be good indicators of soil quality as reflected by the higher density and diversity of soil total microarthropods, Collembola, Acarina and other microarthropods group. The use of microarthropods for soil quality assessment could be effective and relatively inexpensive tool; however, further research is required to evaluate the impact of agricultural practices and elevation gradient on soil microarthropods density, diversity and species composition for the sustainable management of agro ecosystems.展开更多
Cliff deformation behavior after conservation is of great significance for evaluating the conservation effect and discovering the dynamical law of soil. Modeling on deformation behavior is beneficial to the quantitati...Cliff deformation behavior after conservation is of great significance for evaluating the conservation effect and discovering the dynamical law of soil. Modeling on deformation behavior is beneficial to the quantitative evaluation of interactions between soil mass and structures as well as the forecast. Based on cliff conservation engineering of Jiaohe Ruins （the largest raw soil heritage site in the world）, data of horizontal deformation of the upper cliff were obtained by using Nanrui-made NDW-50 displacement device （precision： 0.01 mm, frequency： 15 min^-l）. Regression analysis indicates that deformation behavior models include exponential growth, linear growth and parabolic growth types, while daily deformation presents more intense periodicity （24 h）. The deformation is less than 1.5 mm during monitoring period, which has no impact on the stability of cliff. Deformation behavior provides the mutual duress and interaction between soil and engineering intervention. In addition, deformation mode attaches tensely to the damage pattern of the cliff. The conclusions are of importance to the stability evaluation of the carrier along Silk Road.展开更多
The chloride ion contained in reinforced concrete seriously corrodes the steel surface and damages concrete, resulting in inferior reinforced concrete that strength seriously compromises the entire structure’s safety...The chloride ion contained in reinforced concrete seriously corrodes the steel surface and damages concrete, resulting in inferior reinforced concrete that strength seriously compromises the entire structure’s safety. Consequently, the examination of chloride ions contained in reinforced concrete becomes an important part of a complete quality control procedure. To effectively check the concentration of chloride ions in concrete, the evaluation process should be accurate and precise. Laboratory data ob- tained using existing evaluation methods for the examination of chloride ion are not sufficiently objective to yield reliable results with accuracy and consistency for each sample. An evaluation algorithm with capability to define indices of precision degree (Ep) and accuracy degree (Ea) is presented in this paper. The authors established a statistically reliable index of unbiased estimators and equations to critically examine the laboratory methods’ precision, accuracy degrees and application value for measuring chlorine ion concentration in reinforced concrete.展开更多
Consecutive differential movements of ground to the dryness and the rehydration of the sols are irregular movements of ground related to the phenomenon of withdrawal-swelling. By risk of withdrawal-swelling, one under...Consecutive differential movements of ground to the dryness and the rehydration of the sols are irregular movements of ground related to the phenomenon of withdrawal-swelling. By risk of withdrawal-swelling, one understands the phenomenon ＂natural＂ likely to occur, with a probability of more or less large occurrence. For the phenomenon of withdrawal-swelling of the argillaceous grounds, one will speak about strong, average or weak risk. This article returns within the framework＇s study of risk withdrawal-swelling or dryness-humidification of the argillaceous Mames of the area of Ouled Fayet and Cheraga of Algiers.展开更多
Thermal mass is currently evaluated with ＂admittance＂ which is the ability of the element to exchange heat with the environment and is based on specific heat capacity, thermal conductivity and density. The aim of th...Thermal mass is currently evaluated with ＂admittance＂ which is the ability of the element to exchange heat with the environment and is based on specific heat capacity, thermal conductivity and density. The aim of this study is to evaluate the effect of thermal properties namely, density, specific heat capacity and thermal conductivity on thermal mass. The objective of the study is to carry out laboratory experiments by measuring such thermal properties of concrete mixes with various percentages of GGBS （ground granulated blast furnace slag）, PFA （pulverized fuel ash）, and SF （silica fume） and RCA （recycled coarse aggregates）. The results obtained from these tests would contribute to the evaluation of how such thermal properties influence the thermal admittance and hence the thermal mass performance of sustainable concrete elements in a building system.展开更多
The quality problem of the concrete body and backwall grouting of shaft lining must be taken into consideration during the engineering construction of the shaft. Detection and evaluation are needed to determine the pa...The quality problem of the concrete body and backwall grouting of shaft lining must be taken into consideration during the engineering construction of the shaft. Detection and evaluation are needed to determine the parameters such as the location and depth of drilling. The record of elastic wave can be gained through laying the surveying lines of the ring and ver- tical direction in the shaft lining by the elastic wave method. And specifically, through analyzing the different parameters of seismic attribute such as the velocity of high frequency reflection wave, amplitude and frequency, the abnormal range on the wall or under the wall can be forecasted. The concrete quality of shallow layer in the shaft lining can be evaluated through the velocity of surfer wave. Using the evaluating technique of comprehensive frequency and the phase feature of waveform, the basic features such as inner construction, wall back filling and failure depth of shaft lining can be interpreted from qualitatively to half quantitatively, and the interpreting section can be drawn. The results show that the detection effect for the shaft quality is significant by elastic wave technique, and the delineation of abnormal areas is accurate. Its guidance function is better for pro- duction.展开更多
In the last decade, mass valuation system is applied in Albania in addition to individual valuation system for real estate valuation. This system is used for compiling the land value map and apartments value map. Due ...In the last decade, mass valuation system is applied in Albania in addition to individual valuation system for real estate valuation. This system is used for compiling the land value map and apartments value map. Due to the lack of experience in the compilation of these maps, the methodology of valuation is based on the experiences of other countries with similar development of real estate market. The mass assessment, which is applied in determining the values for specific purposes, such as expropriation, compensation and taxes for property transfer through the methodology adopted for this aim, is analyzed in the light of the finding of issues that accompany this application. The aim of this research is to highlight the problems to provide the ways of overcoming them in order to approximate the values of map values with market values. The mass appraisal process requires effective valuation models and proper management of resources. Its accuracy depends upon the extent and quality of property data available. Because of this reason, it is recommended the usage of the GIS （geographic information system）, an automated system for collection and processing of the data necessary for valuation, as the first point of integration between two process of valuation, individual and mass valuation.展开更多
Soil quality assessment provides a tool for agriculture managers and policy makers to gain a better understanding of how various agricultural systems affect soil resources. Soil quality of Hailun County, a typical soy...Soil quality assessment provides a tool for agriculture managers and policy makers to gain a better understanding of how various agricultural systems affect soil resources. Soil quality of Hailun County, a typical soybean （Glycine max L. Merill） growing area located in Northeast China, was evaluated using soil quality index （SQI） methods. Each SQI was computed using a minimum data set （MDS） selected using principal components analysis （PCA） as a data reduction technique. Eight MDS indicators were selected from 20 physical and chemical soil measurements. The MDS accounted for 74.9% of the total variance in the total data set （TDS）. The SQI values for 88 soil samples were evaluated with linear scoring techniques and various weight methods. The results showed that SQI values correlated well with soybean yield （r = 0.658＊＊） when indicators in MDS were weighted by the regression coefficient computed for each yield and index. Stepwise regression between yield and principal components （PCs） indicated that available boron （AvB）, available phosphorus （AvP）, available potassium （AvK）, available iron （AvFe） and texture were the main factors limiting soybean yield. The method used to select an MDS could not only appropriately assess soil quality but also be used as a powerful tool for soil nutrient diagnosis at the regional level.展开更多
The purity of soil map units and their quality for various uses like land suitability evaluation are always questioned.The main objective of this study was to compare the precision of qualitative land suitability clas...The purity of soil map units and their quality for various uses like land suitability evaluation are always questioned.The main objective of this study was to compare the precision of qualitative land suitability classification based on geostatistical and conventional soil mapping methods for main irrigated crops in the Shahrekord Plain,Central Iran.A regular grid sampling method consisting 104sample points was designed and soil samples were collected.Ordinary kriged maps were achieved for all studied soil attributes after physico-chemical analyses.Afterward,to combine kriged maps and ecological requirements of the studied crops,a script was designed in ILWIS 3.4 software and consequently,kriged qualitative land suitability maps were generated.Conventional qualitative land suitability was also mapped based on the representative pedon analysis in each soil map unit.Finally,comparison of the conventional and kriged maps was carried out using the statistical method,error matrix.The results showed that the overall accuracies of wheat,sugar beet,potato and alfalfa maps were 39.8%,24.3%,18.7%and 18.6%at subclass category,respectively,whereas these values increased to80.9%,82.3%,23.7%and 82.3%at class level,respectively.Hence,it can be stated that thanks to the relative facility of conventional soil survey compared with geostatistical methods,this method can be expressed as a preferable way for handling a usual land suitability evaluation design;but using soil map units as land suitability delineations may lead to unsatisfactory results in estimation of quantity and type of existing limitations.展开更多
文摘[Objective] This study aimed to understand and grasp the soil heavy metal pollution status of agricultural habitat environment in Xi＇an City. [Method] The soil heavy metal pollution status of pollution-free agricultural products-producing areas in 9 counties （districts） of Xi＇an City was investigated. A total of 609 soil samples were collected, and their Cd, Hg, As, Pb and Cr contents were determined. In addition, the heavy metal pollution status of the collected soil samples was evaluated by Nemerow index method. [Result] The pollution in Baqiao, Chang＇an; Gaoling, Lan- tian, Lintong and Yanliang was of grade I, belonging to clean level; the pollution in Hu County, Weiyang and Zhouzhi was of grade II, near the warning line, belong to relatively clean level. There was no large-area soil heavy metal pollution overall. The investigated areas could be used as production bases of pollution-free agricultural products and even high-quality agricultural products. However, the heavy met- als contents in some individual areas exceeded relevant soil environmental quality standards, and they should be avoided or forbidden during regional planning and selection of production area. [Conclusion] Soil heavy metal pollution of agricultural habitat environment in Xi＇an City is generally at good status. Targeting at the future development plan of Xi＇an City, feasible and scientific suggestions are put forward.
基金Project supported by the China Postdoctoral Science Foundation,the Youth Foundation of Sichuan University(No.432028)and the National High-Tech Research and Development Program of China(863 Program)(No.2002AA2Z4251).
文摘A new technique of dimension reduction named projection pursuit is applied to model and evaluatewetland soil quality variations in the Sanjiang Plain, Helongjiang Province, China. By adopting the im-proved real-coded accelerating genetic algorithm (RAGA), the projection direction is optimized and multi-dimensional indexes are converted into low-dimensional space. Classification of wetland soils and evaluationof wetland soil quality variations are realized by pursuing optimum projection direction and projection func-tion value. Therefore, by adopting this new method, any possible human interference can be avoided andsound results can be achieved in researching quality changes and classification of wetland soils.
基金Project(50490270) supported by the National Natural Science Foundation of China
文摘Stability condition and quality evaluation formula of layerlike backfilling roof,Q≥C,where Q denotes is quality index depending on allowable compressive or tensile strength and integrity of backfilling,and C is the technical index depending on mining method and backfilling technology,were inferred according to simply supported beam theorem.Technical treatment measures for instable backfilling roof,including optimum of appropriate filling materials and dosage for excellent flow property and reduction of backfill cost.It is proved that slope equation of backfill slurry in a stope to be filled is y=hexp[x2/(2σ)2)],where h is height of cone and σ2 is mean square,and that optimum drainage point of backfill slurry can be determined by the equation and sizes of stope.Case study indicates that the results can give a theoretical support for quality evaluation and control of layerlike backfilling.
基金Supported by the National Natural Science Foundation of China (Nos.40671145 and 60573115)the Provincial Natural Science Foundation of Guangdong,China (Nos.04300504 and 05006623)
文摘Fuzzy association rules (FARs) can be powerful in assessing regional soil quality, a critical step prior to land planning and utilization; however, traditional FARs mined from soil quality database, ignoring the importance variability of the rules, can be redundant and far from optimal. In this study, we developed a method applying different weights to traditional FARs to improve accuracy of soil quality assessment. After the FARs for soil quality assessment were mined, redundant rules were eliminated according to whether the rules were significant or not in reducing the complexity of the soil quality assessment models and in improving the comprehensibility of FARs. The global weights, each representing the importance of a FAR in soil quality assessment, were then introduced and refined using a gradient descent optimization method. This method was applied to the assessment of soil resources conditions in Guangdong Province, China. The new approach had an accuracy of 87%, when 15 rules were mined, as compared with 76% from the traditional approach. The accuracy increased to 96% when 32 rules were mined, in contrast to 88% from the traditional approach. These results demonstrated an improved comprehensibility of FARs and a high accuracy of the proposed method.
基金Project supported by the National Natural Science Foundation of China (No. 40830535)the National Key Technology R&D Program of China (No. 2007BAC30B02)the Scientific Program of Department of Education, Hebei Province,China (No. Z2008102)
文摘Wetland soil quality degradation caused by large-scale agricultural reclamation on the Sanjiang Plain of Northeast China has been widely reported. A relative soil quality evaluation (RSQE) model and a projection pursuit evaluation (PPE) model based on real-coded accelerating genetic algorithm were introduced to evaluate quality variations in top layers of the main wetland soils on the Sanjiang Plain in 1999 and 2003, respectively. As soil quality degradation boundaries were vague, this study established two fuzzy synthetic evaluation (FSE) models based on the original data and criteria used in the RSQE and PPE models. The outputs of the two FSE models were obtained by choosing two fuzzy composite operators M(∧, ∨) and M(·, ⊕). Statistical analysis showed that the results of the FSE, RSQE, and PPE models were correlated. In particular, outputs of the FSE model using M(·, ⊕) were significantly correlated with those of the RSQE model with r = 0.989 at P < 0.01. Compared with RSQE and PPE models, the FSE model may be more objective in showing soil quality variations and was closer to the natural situation, showing the feasibility and applicability of the FSE model in evaluating soil quality degradation. However, the choice of composite operator was of critical importance. The study of wetland soil quality degradation on the Sanjiang Plain was of scientific and practical significance for protection and management of soils and for sustainable development of agriculture in this area in the future.
基金Project(2011CB013600) supported by State Key Program for Basic Research of ChinaProject(20136201110003) supported by the Education Ministry Doctoral Tutor Foundation of China+1 种基金Project(51368039) supported by the National Natural Science Foundation of ChinaProject(2013-4-94) supported by the Program of Science and Technology Research in Lanzhou City,China
文摘The objective of this work is to obtain the seismic safety coefficient and fracture surface and proceed with the seismic safety evaluation for the rock mass or soil mass surrounding a tunnel,and the limitation of evaluating seismic stability is considered using the pseudo-static strength reduction.By using the finite element software ANSYS and the strength reduction method,new methods of seismic safety evaluation for the rock mass or soil mass surrounding a tunnel are put forward,such as the dynamic finite element static shear strength reduction method and dynamic finite element shear strength reduction method.In order to prove the feasibility of the proposed methods,the results of numerical examples are compared with that of the pseudo-static strength reduction method.The results show that 1) the two methods are both feasible,and the plastic zone first appears near the bottom corners; 2) the safety factor of new method Ⅱ is smaller than that of new method I but generally,and the difference is very small.Therefore,in order to ensure the safety of the structure,two new methods are proposed to evaluate the seismic stability of the rock mass or soil mass surrounding a tunnel.A theoretical basis is provided for the seismic stability of the rock mass or soil mass and the lining surrounding a tunnel and also provided for the engineering application.
文摘The study aimed to evaluate soil quality using microarthopods density, diversity and soil biological quality index （QBS-ar） under different land use systems and elevation gradients. A secondary aim was to determine the relationship among soil biological and physiochemical indicators. Three groups of soil microarthropods were recognized viz. （1） Collembola （38%） （2） Acarina （33%） and （3） other microarthropods （29%）. ANOVA indicated that total microarthropods densities differed significantly with land use and elevation. Population density of Acarina and other mieroarthropods were weakly significant different according to land use, while Collembola and Acarina densities showed highly significant difference with elevation. Total microarthropods, Acarina and Collembola densities were positively significantly correlated with soil organic carbon （SOC） and moisture but negatively correlated with bulk density, pH and temperature of the soil. SOC and soil moisture appeared to be good indicators of soil quality as reflected by the higher density and diversity of soil total microarthropods, Collembola, Acarina and other microarthropods group. The use of microarthropods for soil quality assessment could be effective and relatively inexpensive tool; however, further research is required to evaluate the impact of agricultural practices and elevation gradient on soil microarthropods density, diversity and species composition for the sustainable management of agro ecosystems.
基金Project(2010BAK67B16) supported by the National Science and Technology Pillar Program during the 11th Five-Year Plan Period of China
文摘Cliff deformation behavior after conservation is of great significance for evaluating the conservation effect and discovering the dynamical law of soil. Modeling on deformation behavior is beneficial to the quantitative evaluation of interactions between soil mass and structures as well as the forecast. Based on cliff conservation engineering of Jiaohe Ruins （the largest raw soil heritage site in the world）, data of horizontal deformation of the upper cliff were obtained by using Nanrui-made NDW-50 displacement device （precision： 0.01 mm, frequency： 15 min^-l）. Regression analysis indicates that deformation behavior models include exponential growth, linear growth and parabolic growth types, while daily deformation presents more intense periodicity （24 h）. The deformation is less than 1.5 mm during monitoring period, which has no impact on the stability of cliff. Deformation behavior provides the mutual duress and interaction between soil and engineering intervention. In addition, deformation mode attaches tensely to the damage pattern of the cliff. The conclusions are of importance to the stability evaluation of the carrier along Silk Road.
基金Project (No. NSC-93-2211-E-167-002) supported by the NationalScience Council of Taiwan China
文摘The chloride ion contained in reinforced concrete seriously corrodes the steel surface and damages concrete, resulting in inferior reinforced concrete that strength seriously compromises the entire structure’s safety. Consequently, the examination of chloride ions contained in reinforced concrete becomes an important part of a complete quality control procedure. To effectively check the concentration of chloride ions in concrete, the evaluation process should be accurate and precise. Laboratory data ob- tained using existing evaluation methods for the examination of chloride ion are not sufficiently objective to yield reliable results with accuracy and consistency for each sample. An evaluation algorithm with capability to define indices of precision degree (Ep) and accuracy degree (Ea) is presented in this paper. The authors established a statistically reliable index of unbiased estimators and equations to critically examine the laboratory methods’ precision, accuracy degrees and application value for measuring chlorine ion concentration in reinforced concrete.
文摘Consecutive differential movements of ground to the dryness and the rehydration of the sols are irregular movements of ground related to the phenomenon of withdrawal-swelling. By risk of withdrawal-swelling, one understands the phenomenon ＂natural＂ likely to occur, with a probability of more or less large occurrence. For the phenomenon of withdrawal-swelling of the argillaceous grounds, one will speak about strong, average or weak risk. This article returns within the framework＇s study of risk withdrawal-swelling or dryness-humidification of the argillaceous Mames of the area of Ouled Fayet and Cheraga of Algiers.
文摘Thermal mass is currently evaluated with ＂admittance＂ which is the ability of the element to exchange heat with the environment and is based on specific heat capacity, thermal conductivity and density. The aim of this study is to evaluate the effect of thermal properties namely, density, specific heat capacity and thermal conductivity on thermal mass. The objective of the study is to carry out laboratory experiments by measuring such thermal properties of concrete mixes with various percentages of GGBS （ground granulated blast furnace slag）, PFA （pulverized fuel ash）, and SF （silica fume） and RCA （recycled coarse aggregates）. The results obtained from these tests would contribute to the evaluation of how such thermal properties influence the thermal admittance and hence the thermal mass performance of sustainable concrete elements in a building system.
文摘The quality problem of the concrete body and backwall grouting of shaft lining must be taken into consideration during the engineering construction of the shaft. Detection and evaluation are needed to determine the parameters such as the location and depth of drilling. The record of elastic wave can be gained through laying the surveying lines of the ring and ver- tical direction in the shaft lining by the elastic wave method. And specifically, through analyzing the different parameters of seismic attribute such as the velocity of high frequency reflection wave, amplitude and frequency, the abnormal range on the wall or under the wall can be forecasted. The concrete quality of shallow layer in the shaft lining can be evaluated through the velocity of surfer wave. Using the evaluating technique of comprehensive frequency and the phase feature of waveform, the basic features such as inner construction, wall back filling and failure depth of shaft lining can be interpreted from qualitatively to half quantitatively, and the interpreting section can be drawn. The results show that the detection effect for the shaft quality is significant by elastic wave technique, and the delineation of abnormal areas is accurate. Its guidance function is better for pro- duction.
文摘In the last decade, mass valuation system is applied in Albania in addition to individual valuation system for real estate valuation. This system is used for compiling the land value map and apartments value map. Due to the lack of experience in the compilation of these maps, the methodology of valuation is based on the experiences of other countries with similar development of real estate market. The mass assessment, which is applied in determining the values for specific purposes, such as expropriation, compensation and taxes for property transfer through the methodology adopted for this aim, is analyzed in the light of the finding of issues that accompany this application. The aim of this research is to highlight the problems to provide the ways of overcoming them in order to approximate the values of map values with market values. The mass appraisal process requires effective valuation models and proper management of resources. Its accuracy depends upon the extent and quality of property data available. Because of this reason, it is recommended the usage of the GIS （geographic information system）, an automated system for collection and processing of the data necessary for valuation, as the first point of integration between two process of valuation, individual and mass valuation.
基金Supported by the Knowledge Innovation Program of Chinese Academy of Sciences(No.KSCX1-YW-09-02)the National Basic Research Program of China(No.2013CB127401)+1 种基金the National Natural Science Foundation of China(No.41271309)the International Plant Nutrition Institute (IPNI) China Program
文摘Soil quality assessment provides a tool for agriculture managers and policy makers to gain a better understanding of how various agricultural systems affect soil resources. Soil quality of Hailun County, a typical soybean （Glycine max L. Merill） growing area located in Northeast China, was evaluated using soil quality index （SQI） methods. Each SQI was computed using a minimum data set （MDS） selected using principal components analysis （PCA） as a data reduction technique. Eight MDS indicators were selected from 20 physical and chemical soil measurements. The MDS accounted for 74.9% of the total variance in the total data set （TDS）. The SQI values for 88 soil samples were evaluated with linear scoring techniques and various weight methods. The results showed that SQI values correlated well with soybean yield （r = 0.658＊＊） when indicators in MDS were weighted by the regression coefficient computed for each yield and index. Stepwise regression between yield and principal components （PCs） indicated that available boron （AvB）, available phosphorus （AvP）, available potassium （AvK）, available iron （AvFe） and texture were the main factors limiting soybean yield. The method used to select an MDS could not only appropriately assess soil quality but also be used as a powerful tool for soil nutrient diagnosis at the regional level.
基金Supported by the Vali-e-Asr University of Rafsanjan,Iran(No.518)
文摘The purity of soil map units and their quality for various uses like land suitability evaluation are always questioned.The main objective of this study was to compare the precision of qualitative land suitability classification based on geostatistical and conventional soil mapping methods for main irrigated crops in the Shahrekord Plain,Central Iran.A regular grid sampling method consisting 104sample points was designed and soil samples were collected.Ordinary kriged maps were achieved for all studied soil attributes after physico-chemical analyses.Afterward,to combine kriged maps and ecological requirements of the studied crops,a script was designed in ILWIS 3.4 software and consequently,kriged qualitative land suitability maps were generated.Conventional qualitative land suitability was also mapped based on the representative pedon analysis in each soil map unit.Finally,comparison of the conventional and kriged maps was carried out using the statistical method,error matrix.The results showed that the overall accuracies of wheat,sugar beet,potato and alfalfa maps were 39.8%,24.3%,18.7%and 18.6%at subclass category,respectively,whereas these values increased to80.9%,82.3%,23.7%and 82.3%at class level,respectively.Hence,it can be stated that thanks to the relative facility of conventional soil survey compared with geostatistical methods,this method can be expressed as a preferable way for handling a usual land suitability evaluation design;but using soil map units as land suitability delineations may lead to unsatisfactory results in estimation of quantity and type of existing limitations.
