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In this study a modified optimality criteria (OC) method which uses the Proportional, Integral, Derivative (PID) control to determine the Lagrange multiplier is proposed. The OC method is efficient in density based topology optimization. However, the undetermined Lagrange multiplier should be calculated first. In this study the Lagrange multiplier is taken as the controlled variable of PID controller, which enhances the convergence of the OC method. The constraint violation is taken as system error which updates the Lagrange multiplier. Combining the design variables update scheme in the OC method with the PID control algorithm, a gradually improved structure is produced during iteration. The optimal structure which satisfies the constraint function is obtained finally. The modified method implements simply and saves the computational time. Numerical examples of single material topology optimization validate the performance of the proposed method. Results show that the modified method converges fast with few iterations and short time. Subsequently, the modified method is extended to multi-material topology optimization. Results validate the modified method performs well in time-consuming multi-material problem. [ABSTRACT FROM AUTHOR]

Aims: The aim of the study is to know about which soil factors could influence the accumulation of hesperidin, nobiletin and tangeretin in pericarps of Citrus reticulata ‘Chachi’ (Citrus reticulata cv. Chachiensis).A total of 150 soil samples from 15 profiles and 60 pericarp samples were collected at different orchards cultivated Citrus reticulata ‘Chachi’. The linear regression models, random forest models and structural equation models were established to explore the relationship between soil factors and the three medicinal components. A 2-year field control experiments were designed to verify the direct impact of key elements on hesperidin, nobiletin and tangeretin in pericarps.Soil potassium (K), calcium (Ca), magnesium (Mg), manganese (Mn), pH, Cation exchange capacity (CEC), Salinity and Sand showed the main influences on hesperidin, nobiletin and tangeretin, in which soil elements, particularly K, Ca, Mg and Mn, were relatively important.Adjusting the absorption of elements by Citrus reticulata ‘Chachi’ is one of the effective and convenient methods to increase or decrease the three medicinal components in pericarps.Methods: The aim of the study is to know about which soil factors could influence the accumulation of hesperidin, nobiletin and tangeretin in pericarps of Citrus reticulata ‘Chachi’ (Citrus reticulata cv. Chachiensis).A total of 150 soil samples from 15 profiles and 60 pericarp samples were collected at different orchards cultivated Citrus reticulata ‘Chachi’. The linear regression models, random forest models and structural equation models were established to explore the relationship between soil factors and the three medicinal components. A 2-year field control experiments were designed to verify the direct impact of key elements on hesperidin, nobiletin and tangeretin in pericarps.Soil potassium (K), calcium (Ca), magnesium (Mg), manganese (Mn), pH, Cation exchange capacity (CEC), Salinity and Sand showed the main influences on hesperidin, nobiletin and tangeretin, in which soil elements, particularly K, Ca, Mg and Mn, were relatively important.Adjusting the absorption of elements by Citrus reticulata ‘Chachi’ is one of the effective and convenient methods to increase or decrease the three medicinal components in pericarps.Results: The aim of the study is to know about which soil factors could influence the accumulation of hesperidin, nobiletin and tangeretin in pericarps of Citrus reticulata ‘Chachi’ (Citrus reticulata cv. Chachiensis).A total of 150 soil samples from 15 profiles and 60 pericarp samples were collected at different orchards cultivated Citrus reticulata ‘Chachi’. The linear regression models, random forest models and structural equation models were established to explore the relationship between soil factors and the three medicinal components. A 2-year field control experiments were designed to verify the direct impact of key elements on hesperidin, nobiletin and tangeretin in pericarps.Soil potassium (K), calcium (Ca), magnesium (Mg), manganese (Mn), pH, Cation exchange capacity (CEC), Salinity and Sand showed the main influences on hesperidin, nobiletin and tangeretin, in which soil elements, particularly K, Ca, Mg and Mn, were relatively important.Adjusting the absorption of elements by Citrus reticulata ‘Chachi’ is one of the effective and convenient methods to increase or decrease the three medicinal components in pericarps.Conclusions: The aim of the study is to know about which soil factors could influence the accumulation of hesperidin, nobiletin and tangeretin in pericarps of Citrus reticulata ‘Chachi’ (Citrus reticulata cv. Chachiensis).A total of 150 soil samples from 15 profiles and 60 pericarp samples were collected at different orchards cultivated Citrus reticulata ‘Chachi’. The linear regression models, random forest models and structural equation models were established to explore the relationship between soil factors and the three medicinal components. A 2-year field control experiments were designed to verify the direct impact of key elements on hesperidin, nobiletin and tangeretin in pericarps.Soil potassium (K), calcium (Ca), magnesium (Mg), manganese (Mn), pH, Cation exchange capacity (CEC), Salinity and Sand showed the main influences on hesperidin, nobiletin and tangeretin, in which soil elements, particularly K, Ca, Mg and Mn, were relatively important.Adjusting the absorption of elements by Citrus reticulata ‘Chachi’ is one of the effective and convenient methods to increase or decrease the three medicinal components in pericarps. [ABSTRACT FROM AUTHOR]

A topology optimization method for coupled vibro-acoustic problem based on hybrid finite element-wave based method is proposed. The hybrid finite element-wave based method is used to model the coupled free layer damping structure-acoustics system, and a gradient-based topology optimization formulation is developed by solid isotropic microstructures with penalization method, to obtain optimized layout of free layer damping with the objective of minimizing sound pressure in the acoustic cavity and with constraint defined as the amount of free layer damping. The adjoint variable method for the coupled vibro-acoustic model based on the hybrid finite element-wave based method is also derived as a part of the sensitivity analysis. Numerical example shows that the optimized distribution reduce sound pressure effectively and the calculation time of proposed method is less than the conventional method for topology optimization base on finite element method. Experimental results verify the accuracy of the hybrid finite element-wave based method and the effect of optimized damping material layout is also validated by experiment. [ABSTRACT FROM AUTHOR]

In this study, the discrete adjoint approach with the grid deformation technique based on radial basis function was presented to solve the tough problem that the complex shape of the defrosting duct is very difficult to be optimized with multiple parameters in the improvement of the defrosting performance of vehicle. Firstly, the defrosting performance of a light truck was analyzed. Then the discrete adjoint approach was applied by taking the average Nusselt-number as the objective function. The normal surface sensitivity was used in the deformation of the defrosting duct. After 10 optimization cycles, the optimal model was acquired. The results show that, after optimization, the sum of the average Nusselt-number is increased from 3164.16 to 3350.54, which has a positive effect on improving the convection and heat transfer capacity on the windshield effectively. Compared with the initial model, the airflow of the outlet near the windshield is increased from 95.07 g/s to 96.94 g/s, the defrosting time required by the optimal model is reduced by more than 20s. Therefore, the discrete adjoint approach can optimize the complex shape of defrosting duct with multiple parameters effectively, which provides an effective method in the study of automobile defrosting performance. [ABSTRACT FROM AUTHOR]

An interfacial potential barrier theory to calculate friction and wear is proposed by considering the micro interaction of frictional surfaces. The theory suggests that the performance of friction and wear depends on the magnitude and distribution of the interfacial potential barrier on contact surfaces. The calculation methods of the interfacial potential barrier and standard interfacial potential barrier are then studied and the formulas to calculate the friction force, friction coefficient, and quantity of adhesion wear are derived based on the theory. With its independence and stability, the standard interfacial potential barrier can be used as an index to describe the frictional performance of materials. The calculation results of the friction force with some existing experimental data are consistent with the experimental results performed with an ultra high vacuum atomic-force microscope, which proves that the theory and method are feasible. [ABSTRACT FROM AUTHOR]

A method based on the energy dissipation mechanism of an Independent Oscillator model is used to calculate the frictional force and the friction coefficient of interfacial friction. The friction work is calculated with considering the potential change of contact surfaces during sliding. The potential change can be gained by a universal adhesive energy function. The relationships between frictional force and parameters of a tribo-system, such as surface energy and microstructure of interfacial material, are set up. The calculation results of the known experimental data denote that the frictional force is nearly proportional to the surface energy of the material, nearly inversely proportional to the scaling length, and independent of the lattice constant. The results agree with that of adhesion friction equations. They also agree with the experimental results performed with an atomic-force microscope under the ultra high vacuum condition. [ABSTRACT FROM AUTHOR]