Water swelling rubber (WSR) was prepared by reaction blending SBR and sodium polyacrylate (PAANa). The existing states of water in the WSR was studied by means of DSC and TG. It was found that water exists in three st...Water swelling rubber (WSR) was prepared by reaction blending SBR and sodium polyacrylate (PAANa). The existing states of water in the WSR was studied by means of DSC and TG. It was found that water exists in three states: nonfreezing water, bound freezable water and free water. The relationships between water states and structure of PAANa were investigated. The results showed that the amount of non-freezing water was related to total water content, and the ratio of non-freezing water versus -COONa groups on PAANa (mol/mol) was about 4. However, total water content slightly affected the content of bound freezable water and remarkably affected the amount of free waer.展开更多
Rubber trees (Hevea brasiliensis Müll. Arg.) have been commercially cultivated for a century and a half in Asia, particularly in China, and they constitute a common element of plantation ecosystems in tropical re...Rubber trees (Hevea brasiliensis Müll. Arg.) have been commercially cultivated for a century and a half in Asia, particularly in China, and they constitute a common element of plantation ecosystems in tropical regions. Soil health is fundamental to the sustainable development of rubber plantations. The objective of the study is to explore the influence of different complex ecological cultivation modes on the stability of soil aggregates in rubber based agroforestry systems. In this study, the ecological cultivation mode of rubber—Alpinia oxyphylla plantation, the ecological cultivation mode of rubber—Phrynium hainanense plantations, the ecological cultivation mode of rubber—Homalium ceylanicum plantations and monoculture rubber plantations were selected, and the particle size distribution of soil aggregates and their water stability characteristics were analyzed. The soil depth of 0 - 20 cm and 20 - 40 cm was collected for four cultivation modes. Soil was divided into 6 particle levels > 20 cm. soil was divided into 6 particle levels > 5 mm, 2 - 5 mm, 1 - 2 mm, 0.5 - 1 mm, 0.25 - 0.5 mm, and 0.053 - 0.25 mm according to the wet sieve method. The particle size proportion and water stability of soil aggregates were determined by the wet sieve method. The particle size proportion and water stability of soil aggregates under different ecological cultivation modes were analyzed. The results showed that under different ecological cultivation modes in the shallow soil layer (0 - 20 cm), the rubber—Alpinia oxyphylla plantation and the rubber—Phrynium hainanense plantation promoted the development of dominant soil aggregates towards larger size classes, whereas the situation is the opposite for rubber—Homalium ceylanicum plantation. In soil layer (20 - 40 cm), the ecological cultivation mode of rubber—Phrynium hainanense plantation developed the dominant radial level of soil aggregates to the diameter level of large aggregates. Rubber—Alpinia oxyphylla plantation and rubber—Homalium ceylanicum plantation, three indicators, including the water-stable aggregate content R<sub>0.25</sub> (>0.25 mm water-stable aggregates), mean weight diameter (MWD), and geometric mean diameter (GMD), were all lower than those in the rubber monoculture mode. However, in the rubber—Phrynium hainanense plantation, the water-stable aggregate content R<sub>0.25</sub>, mean weight diameter, and geometric mean diameter were higher than in the rubber monoculture mode, although these differences did not reach statistical significance.展开更多
Rapid road infrastructure development due to an increasing demand of car users resulted in an increase in paved areas including road sites and suppression of green spaces. An integrated solution that can support a cou...Rapid road infrastructure development due to an increasing demand of car users resulted in an increase in paved areas including road sites and suppression of green spaces. An integrated solution that can support a country’s economic development without compromising water pollution is becoming inevitable. Recycling tyres in the form of crumb rubber tyres and mixing it into bituminous paving mixture can increase the recycling rate and minimize cost of incineration process. In dry mixing process, five (5) different variations of Open Graded Wearing (OGW) course road samples were made to make up 1.15 kg in each sample. Each OGW mix contained 4% - 6% bitumen Pen 60/ 70 and fixed 1% of crumb rubber tyres, making the percentage of crumb rubber tyres 14% - 20% of bituminous samples. Bitumen Pen 60/70 mixed with 20% crumb rubber tyres content met the PG 76 bitumen properties. Physical properties of OGW made from crumb rubber modified bitumen (CRMB) were better than standard bitumen only. In a separate water leachate test using ICP-OES equipment, heavy metal leachate of Cu(II), Pb(II), Zn(II) and Cd(II) were present in all OGW CRMB samples at increasing surrounding water temperature from 25℃ to 60℃. However all the heavy metal concentration was very low below the allowable limit of trade effluent standards into water course.展开更多
Rapids and shoals in the channel have a huge impact on the safety of the ship navigation, Based on the principle of a rubber dam can always adjust the height of the dam and raise upstream water level, This thesis crea...Rapids and shoals in the channel have a huge impact on the safety of the ship navigation, Based on the principle of a rubber dam can always adjust the height of the dam and raise upstream water level, This thesis creatively proposed the principle which applied to rapids and shoals in the Channel. In order to achieve the purpose of assisting ship through the channel safely. In this paper, through theoretical calculations verified the rubber dam has characteristics of raising water level, increasing the depth of the shoals, reducing the flow velocity, reducing water surface slope and improving the conditions of navigation. Therefore, this study has a wide range of practical value and application prospects in the project展开更多
为了有效监测环境水体中的有机氯农药(OCPs)残留,本研究开发了一种低消耗、弱基质效应、经济便捷的固相微萃取技术测定水中13种OCPs残留的方法。应用具有强选择性的硅橡胶(SR)薄膜为固相吸附材料,制备了简便易操作的固相萃取瓶,通过优...为了有效监测环境水体中的有机氯农药(OCPs)残留,本研究开发了一种低消耗、弱基质效应、经济便捷的固相微萃取技术测定水中13种OCPs残留的方法。应用具有强选择性的硅橡胶(SR)薄膜为固相吸附材料,制备了简便易操作的固相萃取瓶,通过优化萃取方式、萃取时间、洗脱溶剂以及洗脱方式等条件,选择涡旋10 min进行SR薄膜对目标物的萃取,利用5 mL V_(正己烷):V_(乙酸乙酯)=1:1溶液洗脱SR薄膜上目标物,采用气相色谱仪进行检测。结果表明:方法检出限在0.001~0.132μg/L之间,定量限为0.2μg/L;决定系数(R^(2))>0.9973;在0.2、1、20μg/L 3个添加水平下,13种农药在水中OCPs的平均回收率在73%~109%之间,相对标准偏差在0.5%~13%之间(n=5)。利用该方法对巢湖、南淝河等合肥市内主要河流进行了13种OCPs残留的检测,结果发现13种OCPs的最高检出质量浓度为3.64μg/L。与已所报道的方法相比,该方法具有灵敏度高、操作简便、成本低等特点,在环境水体OCPs多残留痕量监测领域具有良好的应用前景。展开更多
基金Project supported by the National Natural Science Foundation of China.
文摘Water swelling rubber (WSR) was prepared by reaction blending SBR and sodium polyacrylate (PAANa). The existing states of water in the WSR was studied by means of DSC and TG. It was found that water exists in three states: nonfreezing water, bound freezable water and free water. The relationships between water states and structure of PAANa were investigated. The results showed that the amount of non-freezing water was related to total water content, and the ratio of non-freezing water versus -COONa groups on PAANa (mol/mol) was about 4. However, total water content slightly affected the content of bound freezable water and remarkably affected the amount of free waer.
文摘Rubber trees (Hevea brasiliensis Müll. Arg.) have been commercially cultivated for a century and a half in Asia, particularly in China, and they constitute a common element of plantation ecosystems in tropical regions. Soil health is fundamental to the sustainable development of rubber plantations. The objective of the study is to explore the influence of different complex ecological cultivation modes on the stability of soil aggregates in rubber based agroforestry systems. In this study, the ecological cultivation mode of rubber—Alpinia oxyphylla plantation, the ecological cultivation mode of rubber—Phrynium hainanense plantations, the ecological cultivation mode of rubber—Homalium ceylanicum plantations and monoculture rubber plantations were selected, and the particle size distribution of soil aggregates and their water stability characteristics were analyzed. The soil depth of 0 - 20 cm and 20 - 40 cm was collected for four cultivation modes. Soil was divided into 6 particle levels > 20 cm. soil was divided into 6 particle levels > 5 mm, 2 - 5 mm, 1 - 2 mm, 0.5 - 1 mm, 0.25 - 0.5 mm, and 0.053 - 0.25 mm according to the wet sieve method. The particle size proportion and water stability of soil aggregates were determined by the wet sieve method. The particle size proportion and water stability of soil aggregates under different ecological cultivation modes were analyzed. The results showed that under different ecological cultivation modes in the shallow soil layer (0 - 20 cm), the rubber—Alpinia oxyphylla plantation and the rubber—Phrynium hainanense plantation promoted the development of dominant soil aggregates towards larger size classes, whereas the situation is the opposite for rubber—Homalium ceylanicum plantation. In soil layer (20 - 40 cm), the ecological cultivation mode of rubber—Phrynium hainanense plantation developed the dominant radial level of soil aggregates to the diameter level of large aggregates. Rubber—Alpinia oxyphylla plantation and rubber—Homalium ceylanicum plantation, three indicators, including the water-stable aggregate content R<sub>0.25</sub> (>0.25 mm water-stable aggregates), mean weight diameter (MWD), and geometric mean diameter (GMD), were all lower than those in the rubber monoculture mode. However, in the rubber—Phrynium hainanense plantation, the water-stable aggregate content R<sub>0.25</sub>, mean weight diameter, and geometric mean diameter were higher than in the rubber monoculture mode, although these differences did not reach statistical significance.
文摘Rapid road infrastructure development due to an increasing demand of car users resulted in an increase in paved areas including road sites and suppression of green spaces. An integrated solution that can support a country’s economic development without compromising water pollution is becoming inevitable. Recycling tyres in the form of crumb rubber tyres and mixing it into bituminous paving mixture can increase the recycling rate and minimize cost of incineration process. In dry mixing process, five (5) different variations of Open Graded Wearing (OGW) course road samples were made to make up 1.15 kg in each sample. Each OGW mix contained 4% - 6% bitumen Pen 60/ 70 and fixed 1% of crumb rubber tyres, making the percentage of crumb rubber tyres 14% - 20% of bituminous samples. Bitumen Pen 60/70 mixed with 20% crumb rubber tyres content met the PG 76 bitumen properties. Physical properties of OGW made from crumb rubber modified bitumen (CRMB) were better than standard bitumen only. In a separate water leachate test using ICP-OES equipment, heavy metal leachate of Cu(II), Pb(II), Zn(II) and Cd(II) were present in all OGW CRMB samples at increasing surrounding water temperature from 25℃ to 60℃. However all the heavy metal concentration was very low below the allowable limit of trade effluent standards into water course.
文摘Rapids and shoals in the channel have a huge impact on the safety of the ship navigation, Based on the principle of a rubber dam can always adjust the height of the dam and raise upstream water level, This thesis creatively proposed the principle which applied to rapids and shoals in the Channel. In order to achieve the purpose of assisting ship through the channel safely. In this paper, through theoretical calculations verified the rubber dam has characteristics of raising water level, increasing the depth of the shoals, reducing the flow velocity, reducing water surface slope and improving the conditions of navigation. Therefore, this study has a wide range of practical value and application prospects in the project
文摘为了有效监测环境水体中的有机氯农药(OCPs)残留,本研究开发了一种低消耗、弱基质效应、经济便捷的固相微萃取技术测定水中13种OCPs残留的方法。应用具有强选择性的硅橡胶(SR)薄膜为固相吸附材料,制备了简便易操作的固相萃取瓶,通过优化萃取方式、萃取时间、洗脱溶剂以及洗脱方式等条件,选择涡旋10 min进行SR薄膜对目标物的萃取,利用5 mL V_(正己烷):V_(乙酸乙酯)=1:1溶液洗脱SR薄膜上目标物,采用气相色谱仪进行检测。结果表明:方法检出限在0.001~0.132μg/L之间,定量限为0.2μg/L;决定系数(R^(2))>0.9973;在0.2、1、20μg/L 3个添加水平下,13种农药在水中OCPs的平均回收率在73%~109%之间,相对标准偏差在0.5%~13%之间(n=5)。利用该方法对巢湖、南淝河等合肥市内主要河流进行了13种OCPs残留的检测,结果发现13种OCPs的最高检出质量浓度为3.64μg/L。与已所报道的方法相比,该方法具有灵敏度高、操作简便、成本低等特点,在环境水体OCPs多残留痕量监测领域具有良好的应用前景。
