The technique of adaptive tree mesh is an effective way to reduce computational cost through automatic adjustment of cell size according to necessity. In the present study, the 2D numerical N-S solver based on the ada...The technique of adaptive tree mesh is an effective way to reduce computational cost through automatic adjustment of cell size according to necessity. In the present study, the 2D numerical N-S solver based on the adaptive quadtree mesh system was extended to a 3D one, in which a spatially adaptive oetree mesh system and multiple particle level set method were adopted for the convenience to deal with the air-water-structure multiple-medium coexisting domain. The stretching process of a dumbbell was simulated and the results indicate that the meshes are well adaptable to the free surface. The collapsing process of water column impinging a circle cylinder was simulated and from the results, it can be seen that the processes of fluid splitting and merging are properly simulated. The interaction of second-order Stokes waves with a square cylinder was simulated and the obtained drag force is consistent with the result by the Morison＇s wave force formula with the coefficient values of the stable drag component and the inertial force component bein~ set as 2.54.展开更多
This study aimed to determine the influence of different rates of K （potassium） and K foliar application on the quality and plant nutrition condition of 13-year old ＇Magallanes＇ pummelo trees [Citrus maxima （Burm...This study aimed to determine the influence of different rates of K （potassium） and K foliar application on the quality and plant nutrition condition of 13-year old ＇Magallanes＇ pummelo trees [Citrus maxima （Burm. ex Rumph.） Merr.]. The experiment was conducted at SODACO （South Davao Corporation） farm, Davao City, Philippines from March to October 2010. Five treatments with increasing K levels were applied per tree： control, no K, 150 g K basal, 225 g K basal and 225 g K basal ＋ foliar application. Application of 225 g K rates positively influenced fruit quality of pummelo. Fruit pulp diameter and juice weight increased while peel thickness decreased. The 225 g K rates also increased juice pH, TA （titrable acidity） and TSS （total soluble solids） per tree. The yield of total phenol, flavonoid, vitamin C and oil per tree increased with 225 g K application. Results of the soil analysis before and after the conduct of the study showed an evidence of fertilizer absorption by the trees. It was also observed that foliar fertilization reduced soil acidity. This indicates the important role of K in improving the nutrient utilization and quality of ＇Magallanes＇ pummelo.展开更多
Logging residue can be defined as any form of wood, which under the highest stage of technological development could be used in manufacturing but is left in the forest during logging. Lumber production from logging re...Logging residue can be defined as any form of wood, which under the highest stage of technological development could be used in manufacturing but is left in the forest during logging. Lumber production from logging residues of a previous logging activity by a timber firm was undertaken with the objective of determining the suitability of utilizing buttressed-stumps as raw material for the timber industry. A horizontal mobile bandsaw machine was used to process the buttressed-stumps into lumber. The machine was characterized by a thin-kerr sawing technology （kerf-width 1.6 mm） compared to the conventional bandsaw machines of kerr-widths ranging from 3.0-4.5 mm. Lumber value and volume yields, fuel consumption rate, frequency of tool replacement and lumber production rate were assessed. Results indicated that there is the potential to increase timber production from logging residues by utilizing buttressed-stumps. Lumber value and volume yields of eight timber species investigated in this study ranged from 5%-31% and 34%-54% respectively. Fuel consumption rate which increased with increasing wood density, ranged from 5-14.5 liters/m3 of lumber produced. Frequency of saw replacement increased with increasing wood density. The number of saws required to produce one cubic meter of lumber, ranged from 1 to 7. Lumber production rate ranged from 0.10-0.38 m3/hour, increasing with decreasing wood density.展开更多
基金Supported by the National Natural Science Foundation of China(No.51379143 and No.51109018)the Foundation for Innovative Research Groups of the National Natural Science Foundation of China(No.51021004)+1 种基金the Open Foundation of Key Laboratory of Water-Sediment Science and Water Disaster Prevention of Hunan Province(No.2014SS01)the Open Foundation of State Key Laboratory of Hydraulic Engineering Simulation and Safety(No.HSSKLTJU-201208)
文摘The technique of adaptive tree mesh is an effective way to reduce computational cost through automatic adjustment of cell size according to necessity. In the present study, the 2D numerical N-S solver based on the adaptive quadtree mesh system was extended to a 3D one, in which a spatially adaptive oetree mesh system and multiple particle level set method were adopted for the convenience to deal with the air-water-structure multiple-medium coexisting domain. The stretching process of a dumbbell was simulated and the results indicate that the meshes are well adaptable to the free surface. The collapsing process of water column impinging a circle cylinder was simulated and from the results, it can be seen that the processes of fluid splitting and merging are properly simulated. The interaction of second-order Stokes waves with a square cylinder was simulated and the obtained drag force is consistent with the result by the Morison＇s wave force formula with the coefficient values of the stable drag component and the inertial force component bein~ set as 2.54.
文摘This study aimed to determine the influence of different rates of K （potassium） and K foliar application on the quality and plant nutrition condition of 13-year old ＇Magallanes＇ pummelo trees [Citrus maxima （Burm. ex Rumph.） Merr.]. The experiment was conducted at SODACO （South Davao Corporation） farm, Davao City, Philippines from March to October 2010. Five treatments with increasing K levels were applied per tree： control, no K, 150 g K basal, 225 g K basal and 225 g K basal ＋ foliar application. Application of 225 g K rates positively influenced fruit quality of pummelo. Fruit pulp diameter and juice weight increased while peel thickness decreased. The 225 g K rates also increased juice pH, TA （titrable acidity） and TSS （total soluble solids） per tree. The yield of total phenol, flavonoid, vitamin C and oil per tree increased with 225 g K application. Results of the soil analysis before and after the conduct of the study showed an evidence of fertilizer absorption by the trees. It was also observed that foliar fertilization reduced soil acidity. This indicates the important role of K in improving the nutrient utilization and quality of ＇Magallanes＇ pummelo.
文摘Logging residue can be defined as any form of wood, which under the highest stage of technological development could be used in manufacturing but is left in the forest during logging. Lumber production from logging residues of a previous logging activity by a timber firm was undertaken with the objective of determining the suitability of utilizing buttressed-stumps as raw material for the timber industry. A horizontal mobile bandsaw machine was used to process the buttressed-stumps into lumber. The machine was characterized by a thin-kerr sawing technology （kerf-width 1.6 mm） compared to the conventional bandsaw machines of kerr-widths ranging from 3.0-4.5 mm. Lumber value and volume yields, fuel consumption rate, frequency of tool replacement and lumber production rate were assessed. Results indicated that there is the potential to increase timber production from logging residues by utilizing buttressed-stumps. Lumber value and volume yields of eight timber species investigated in this study ranged from 5%-31% and 34%-54% respectively. Fuel consumption rate which increased with increasing wood density, ranged from 5-14.5 liters/m3 of lumber produced. Frequency of saw replacement increased with increasing wood density. The number of saws required to produce one cubic meter of lumber, ranged from 1 to 7. Lumber production rate ranged from 0.10-0.38 m3/hour, increasing with decreasing wood density.
