EFFECT OF DIFFERENT BULKING AGENTS ON TRANSFORMATION OF NITROGEN DURING SEWAGE SLUDGE COMPOSTING

以稻草、木屑、树叶为填料,采用人工翻堆堆肥工艺,研究了4种填料组合下城市污泥堆肥过程中的温度变化及层次差异。结果表明,与填料的木质素含量有关,填料木质素含量低,堆体温度升高快,最高温度较高。堆肥过程中堆体各层次的温度均为中层高于上层和下层,堆肥初期,堆体上层温度低于下层,随后则高于下层,堆肥腐熟时3层温度趋于一致。以稻草等木质素含量低的物质作填料,堆体上层温度升高快,各层次最高温到达时间差异小,最高温相差大。Rice straw,sawdust and tree leaves were used as bulking agents to investigate the changes in temperature,total N,NH~+_4-N and NO~-_3-N during sewage sludge composting by artificial turnover protocol.The results showed that using rice straw or rice straw plus sawdust as bulking agents was beneficial to killing the pathogens and accelerating composting due to faster temperature increase and a longer high-temperature period.Water soluble NH~+_4-N increased to the maximum on the 14~(th) day of composting,followed by a rapid decline thereafter.The content of NO~-_3-N started to rise gradually 14 days after the commencement of composting.Contents of NH~+_4-N and NO~-_3-N in the composting piles with sawdust or tree leaves were lower than those in the piles with rice straw or rice straw plus sawdust.Total N in the piles decreased during composting due to loss of NH_3 through volatilization,mainly in the first 28 days of composting.Sawdust helped to decrease N loss.重庆市科委攻关资助项目(2004

Application of Ground LiDAR for The Investigation of Outcrop Discontinuities and Estimation of Associated Engineering Characteristics

Reliable and direct information about rock slope materials and discontinuity parameters from field investigation are keys to engineering design, structure maintenance and soil/water conservation. Under the impact of global climate change and the surge in extreme weather events, rapid and accurate equipment or procedures for geological engineering surveys are necessary to harmonize engineering facilities with natural environment. This study utilizes 3D laser scanning technology (also known as ground LiDAR), which obtains the coordinates of surface geometry rapidly in point clouds, to survey two outcrops. Applying ground LiDAR in a geological survey, we compare the results with those provided by the International Society of Rock Mechanics, and analyze the slope stability. This study also discusses the applicability and limitations of ground LiDAR technology in discontinuity investigation and estimation of rock mass engineering characteristics. Suggested operating procedures for the use of ground LiDAR technology in outcrop surveys are provided accordingly. The results show that ground LiDAR technology reduces the in-situ operation time significantly, thus facilitating efficient discontinuity surveys and outcrop parameters evaluation. However, the quantities of office work and the accuracy of point clouds depend on the velocity and accuracy of ground LiDAR surveys. Therefore, inspection of survey results and output parameter, along with the application and operating specifications of geological surveys, including point cloud resolution, reasonable error of superimposition, inspection procedures and data analysis, still await further research.岩石工程道路邊坡經現地調查獲得可靠、直接的岩石材料種類與不連續面參數，為確保工程設計施工、設施營運維護及環境水土保持之關鍵資訊。在近年全球氣候變遷與極端氣候事件規模與頻率加大的衝擊下，迅速、精準的工程地質調查工具與作業方法，為落實工程設施與自然環境永續發展的不二法門。本研究利用三維雷射掃描技術 (又稱光達技術，|iDAR)，運用其可快速取得露頭表面幾何坐標描述點雲的特性，透過2處露頭現地地質調查，探討地面光達在工址地質調查之應用，並比較國際岩石力學學會建議工址現地調查作業方法所獲得的參數，分析評估邊坡的穩定特性，據以提出地面光達應用於露頭不連續面調查與岩體工程特性評估的適用性與限制，並提出地面光達應用於露頭調查的作業程序。研究結果顯示，地面光達技術可大幅縮減現地調查作業時間，為露頭不連續面調查與參數評估的新利器，由於室內分析工作量和點雲的精度決定了|iDAR應用於露頭不連續面調查的速度與精準度，未來針對調查成果與產出參數的檢核、在地質調查的應用與作業規範，包括點雲解析度、疊合容許誤差以及資料分析與檢核程序等，有待進一步深入研究

基于CDEM的高桩码头在地震作用下破坏模式数值模拟研究

将有限体积法(FVM)与基于连续介质的离散元方法(CDEM)相结合,模拟了高桩码头在地震作用下的破坏模式。在验证了基于有限体积法的CDEM方法可行的基础上,选取了实际的高桩码头模型,采用EL-centro波模拟高桩码头在波动作用下的破坏演化过程,同时提取了梁顶关键的位移进行了详细的分析,得出了破坏过程的位移逐步变化,为高桩码头考虑地震作用的设计提供了有价值的技术参考

拟静力方法适用范围及地震力计算

通过动力时程方法求出地震作用系数,分析拟静力方法计算偏于保守的原因。并依据动力时程方法的计算结果给出拟静力方法的适用范围并修正拟静力方法的地震作用力和地震作用系数公式。数值模拟结果表明,坡高与波长的比是影响边坡稳定性的重要因素,而坡角对其影响则较小;其次,拟静力方法的适用范围是非常有限的,在坡高很小时,拟静力方法的计算结果偏于危险,当坡高较大时,拟静力方法计算结果偏于保守;在远场和近场地震作用下,地震动加速度峰值系数不同,远场地震主要是水平地震作用力,近场地震主要是竖向地震作用力

Effects of Different Bulking Agents on Nitrogen Transformation During Sewage Sludge Composting

以稻草、木屑、树叶为填料,采用人工翻堆好氧堆肥工艺,通过测定堆肥过程中的温度、pH、TN、NH4+-N和NO3--N的变化,研究了填料对堆肥过程中氮的转化及损失的影响.结果表明:以稻草、木屑+稻草作填料,堆体的温度升高快,高温期持续的时间长,有利于污泥堆肥的快速腐熟和灭菌;堆肥初期,堆体NH4+-N含量逐渐升高,14 d时达最大值,然后迅速下降,在堆肥结束时达到一个较低的水平,NO3--N含量在14 d后逐渐升高,仅以木屑或树叶作填料的堆体,其水溶性NH4+-N,NO3--N含量均较以稻草、木屑+稻草作填料的堆体低;堆肥后堆体的全氮含量降低,仅以稻草为填料的堆体,其氮损失率最高,木屑能降低氮素的损失;氮素的损失80%发生在堆肥的前期28 d,此阶段应采取措施降低氮素的损失.Bulking agents,including rice straw,sawdust and tree leaves,were used to investigate the changes of temperature,TN,NH+4-N and NO-3-N during the sewage sludge composting by artificial turnover protocol.The results showed that using rice straw or rice straw plus sawdust as the bulking agents was beneficial for killing the pathogens and accelerating the speed of composting due to faster temperature increase and a longer duration of the high temperature period.Water-soluble NH+4-N was the highest on the 14th day of composting,which was followed by a rapid decline,while NO-3-N increased on the 14th day of composting.The contents of soluble NH+4-N and NO-3-N in the pile with sawdust or tree leaves were lower than the piles with rice straw or rice straw plus sawdust.The content of TN of the pile decreased during the process of composting due to NH 3 loss through volatilization,which occurred during the first 28 days of composting.Compost pile with rice straw resulted in a higher N loss,while sawdust decreased N loss.重庆市科委攻关资助项目(2004

Effect of Compound Pollution of Zn-Cd in Purple Soil on Lettuce under Simulating Acid Rain

通过盆栽实验研究了酸雨影响下紫色土Zn-Cd复合污染对莴笋的影响。结果表明:酸雨影响下,Zn为低水平时,Zn-Cd复合污染对莴笋表现为拮抗增产;Zn为高水平时,复合污染对莴笋表现为协同减产。重金属累积量在Zn-Cd复合污染时表现为Cd对Zn的作用和Zn对Cd的作用恰好相反:在Zn为低浓度时,Zn促进了莴笋对Cd的吸收,Cd抑制了莴笋对Zn的吸收;在Zn为高浓度时,Zn抑制了莴笋对Cd的吸收,Cd促进了莴笋对Zn的吸收。酸雨对莴笋的生长起抑制作用,莴笋生物量随着酸雨pH值的升高而增加,而莴笋地上部分重金属的富集能力也随之增强,并且Cd的富集能力明显大于Zn,莴笋可食部分毒性也随之增大。Pot experiments under simulating acid rain were conducted to study the effect of Cd-Zn compound polluted on lettuce(Lactuca sativa var.angustana Irish) in purple soil.The results showed that Zn counteracted Cd to improve the yield when the concentration of Zn was low,Zn also cooperated with Cd to reduce the yield when the concentration of Zn was high.The Cd-Zn compound pollution indicated that Zn promoted the absorption of Cd by the lettuce,and Cd restrained the absorption of Cd by the lettuce,under the condition of low Zn level;Zn restrained the absorption of Cd by the lettuce,and Cd promoted the absorption of Cd by the lettuce,under the condition of high Zn level.Acid rain restrained the growth of lettuce.Biology quantity of lettuce and cumulating coefficient of Zn, Cd in lettuce increased when pH of the acid rain increased,and cumulating ability of Cd was bigger than that of Zn,which resulted in heavy metal toxicity of edible part increasing.重庆市生态环境保护行动计划项