This work illustrates the application of the “Second Order Comprehensive Adjoint Sensitivity Analysis Methodology” (2<sup>nd</sup>-CASAM) to a mathematical model that can simulate the evolution and/or tr...This work illustrates the application of the “Second Order Comprehensive Adjoint Sensitivity Analysis Methodology” (2<sup>nd</sup>-CASAM) to a mathematical model that can simulate the evolution and/or transmission of particles in a heterogeneous medium. The model response is the value of the model’s state function (particle concentration or particle flux) at a point in phase-space, which would simulate a pointwise measurement of the respective state function. This paradigm model admits exact closed-form expressions for all of the 1<sup>st</sup>- and 2<sup>nd</sup>-order response sensitivities to the model’s uncertain parameters and domain boundaries. These closed-form expressions can be used to verify the numerical results of production and/or commercial software, e.g., particle transport codes. Furthermore, this paradigm model comprises many uncertain parameters which have relative sensitivities of identical magnitudes. Therefore, this paradigm model could serve as a stringent benchmark for inter-comparing the performances of all deterministic and statistical sensitivity analysis methods, including the 2<sup>nd</sup>-CASAM.展开更多
This work continues the illustrative application of the “Second Order Comprehensive Adjoint Sensitivity Analysis Methodology” (2<sup>nd</sup>-CASAM) to a benchmark mathematical model that can simulate th...This work continues the illustrative application of the “Second Order Comprehensive Adjoint Sensitivity Analysis Methodology” (2<sup>nd</sup>-CASAM) to a benchmark mathematical model that can simulate the evolution and/or transmission of particles in a heterogeneous medium. The model response considered in this work is a reaction-rate detector response, which provides the average interactions of particles with the respective detector or, alternatively, the time-average of the concentration of a mixture of substances in a medium. The definition of this model response includes both uncertain boundary points of the benchmark, thereby providing both direct and indirect contributions to the response sensitivities stemming from the boundaries. The exact expressions for the 1<sup>st</sup>- and 2<sup>nd</sup>-order response sensitivities to the boundary and model parameters obtained in this work can serve as stringent benchmarks for inter-comparing the performances of all (deterministic and statistical) sensitivity analysis methods.展开更多
Nitrification inhibitors are widely used in agriculture to mitigate nitrous oxide(N_(2)O)emission and increase crop yield.However,no concrete information on their mitigation of N_(2)O emission is available under soil ...Nitrification inhibitors are widely used in agriculture to mitigate nitrous oxide(N_(2)O)emission and increase crop yield.However,no concrete information on their mitigation of N_(2)O emission is available under soil and environmental conditions as in Pakistan.A field experiment was established using a silt clay loam soil from Peshawar,Pakistan,to study the effect of urea applied in combination with a nitrification inhibitor,nitrapyrin(2-chloro-6-tri-chloromethyl pyridine),and/or a plant growth regulator,gibberellic acid(GA_3),on N_(2)O emission and the nitrogen(N)uptake efficiency of maize.The experimental design was a randomized complete block with five treatments in four replicates:control with no N(CK),urea(200 kg N ha^(-1))alone,urea in combination with nitrapyrin(700 g ha^(-1)),urea in combination with GA_3(60 g ha^(-1)),and urea in combination with nitrapyrin and GA_3.The N_(2)O emission,yield,N response efficiency,and total N uptake were measured during the experimental period.The treatment with urea and nitrapyrin reduced total N_(2)O emission by 39%–43%and decreased yield-scaled N_(2)O emission by 47%–52%,relative to the treatment with urea alone.The maize plant biomass,grain yield,and total N uptake increased significantly by 23%,17%,and 15%,respectively,in the treatment with urea and nitrapyrin,relative to the treatment with urea alone,which was possibly due to N saving,lower N loss,and increased N uptake in the form of ammonium;they were further enhanced in the treatment with urea,nitrapyrin,and GA_3 by 27%,36%,and 25%,respectively,probably because of the stimulating effect of GA_3 on plant growth and development and the reduction in biotic and abiotic stresses.These results suggest that applying urea in combination with nitrapyrin and GA_3 has the potential to mitigate N_(2)O emission,improve N response efficiency,and increase maize yield.展开更多
文摘This work illustrates the application of the “Second Order Comprehensive Adjoint Sensitivity Analysis Methodology” (2<sup>nd</sup>-CASAM) to a mathematical model that can simulate the evolution and/or transmission of particles in a heterogeneous medium. The model response is the value of the model’s state function (particle concentration or particle flux) at a point in phase-space, which would simulate a pointwise measurement of the respective state function. This paradigm model admits exact closed-form expressions for all of the 1<sup>st</sup>- and 2<sup>nd</sup>-order response sensitivities to the model’s uncertain parameters and domain boundaries. These closed-form expressions can be used to verify the numerical results of production and/or commercial software, e.g., particle transport codes. Furthermore, this paradigm model comprises many uncertain parameters which have relative sensitivities of identical magnitudes. Therefore, this paradigm model could serve as a stringent benchmark for inter-comparing the performances of all deterministic and statistical sensitivity analysis methods, including the 2<sup>nd</sup>-CASAM.
文摘This work continues the illustrative application of the “Second Order Comprehensive Adjoint Sensitivity Analysis Methodology” (2<sup>nd</sup>-CASAM) to a benchmark mathematical model that can simulate the evolution and/or transmission of particles in a heterogeneous medium. The model response considered in this work is a reaction-rate detector response, which provides the average interactions of particles with the respective detector or, alternatively, the time-average of the concentration of a mixture of substances in a medium. The definition of this model response includes both uncertain boundary points of the benchmark, thereby providing both direct and indirect contributions to the response sensitivities stemming from the boundaries. The exact expressions for the 1<sup>st</sup>- and 2<sup>nd</sup>-order response sensitivities to the boundary and model parameters obtained in this work can serve as stringent benchmarks for inter-comparing the performances of all (deterministic and statistical) sensitivity analysis methods.
基金funded by the International Atomic Energy Agency through a Coordinated Research Project(CRP D1.50.16)“Minimizing Farming Impacts on Climate Change by Enhancing Carbon and Nitrogen Capture and Storage in Agro-Ecosystems”(18595)of Soil and Water Management and Crop Nutrition Section,Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture,Department of Nuclear Sciences and Applications。
文摘Nitrification inhibitors are widely used in agriculture to mitigate nitrous oxide(N_(2)O)emission and increase crop yield.However,no concrete information on their mitigation of N_(2)O emission is available under soil and environmental conditions as in Pakistan.A field experiment was established using a silt clay loam soil from Peshawar,Pakistan,to study the effect of urea applied in combination with a nitrification inhibitor,nitrapyrin(2-chloro-6-tri-chloromethyl pyridine),and/or a plant growth regulator,gibberellic acid(GA_3),on N_(2)O emission and the nitrogen(N)uptake efficiency of maize.The experimental design was a randomized complete block with five treatments in four replicates:control with no N(CK),urea(200 kg N ha^(-1))alone,urea in combination with nitrapyrin(700 g ha^(-1)),urea in combination with GA_3(60 g ha^(-1)),and urea in combination with nitrapyrin and GA_3.The N_(2)O emission,yield,N response efficiency,and total N uptake were measured during the experimental period.The treatment with urea and nitrapyrin reduced total N_(2)O emission by 39%–43%and decreased yield-scaled N_(2)O emission by 47%–52%,relative to the treatment with urea alone.The maize plant biomass,grain yield,and total N uptake increased significantly by 23%,17%,and 15%,respectively,in the treatment with urea and nitrapyrin,relative to the treatment with urea alone,which was possibly due to N saving,lower N loss,and increased N uptake in the form of ammonium;they were further enhanced in the treatment with urea,nitrapyrin,and GA_3 by 27%,36%,and 25%,respectively,probably because of the stimulating effect of GA_3 on plant growth and development and the reduction in biotic and abiotic stresses.These results suggest that applying urea in combination with nitrapyrin and GA_3 has the potential to mitigate N_(2)O emission,improve N response efficiency,and increase maize yield.
