One-dimensional Steady-state Model for Gas Pressure Distribution in Municipal Solid Waste Landfills

Gas pressure distribution in landfills is of great importance to control hazards and improve recovery of landfill gas. An one-dimensional steady-state model and its solving approach are presented for gas pressure distribution in layered waste landfills. The model can be used to investigate the gas pressure distribution of the landfill with horizontal gas collection layers having specified pressure or flux. The influences of layered properties, horizontal permeable layer under final cover and horizontal gas collection layers and bottom leachate drainage systems dually serving as gas collection layers on gas pressure distribution are investigated. The results of parameter analyses using the presented model show that the assumption that homogenizations of gas generation rate and gas permeability through a landfill considerably overestimate gas pressure in landfill; horizontal permeable layer under final cover and horizontal gas collection layers can effectively reduce gas pressure in landfills; the bottom leachate drainage systems dually serving as gas collection layers can significantly reduce the gas pressure in the lower portion of landfills. The presented model provides a useful tool in the designing of landfill gas collection systems, such as, the positions and spacing of horizontal gas collection layers and pump section.     

Analysis of the Medium Pressure Range in Urban Gas Transmission and Distribution System

According to the analysis of technology and economy about the gas supply with the medium pressure in gas pipeline network of urban gas transmission and distribution system,a more economical and feasible pressure value is obtained.     

Experimental Simulation of Landfill Gas Production from MSW Co-disposed with Wastewater Sludge

In this paper, the landfill gas generation process was investigated by a landfill lysimeter of municipal solid waste (MSW) co-disposed with wastewater sludge. The experimental results show that the wastewater sludge played a role of inoculation in MSW degradation process and accelerated organic waste decomposition. Compared with the MSW landfill alone, the landfill gas generation rate of MSW co-disposed with sludge was higher by about 30%. The average CH 4 content in landfill gas reached 64%, which was much higher than in case of MSW landfill alone and useful for landfill gas utilization. It is also proved that co-disposal of sludge with MSW is a good choice for beneficial use of sludge.     

Analysis of the Optimal Effect Radius of Regulator Station in Urban Gas Distribution Network with Medium Pressure

In urban gas network with multiple pressure ranges, there is an optimal effect radius, for which the annual calculating cost is minimal. According to the analysis of technology and economy about the gas supply with the medium pressure in urban gas transmission and distribution system, the optimal effect radius of regulator station in medium pressure gas network has been obtained.     

Simulation of the Effects of Water Migration on Municipal Solid Waste Biodegradation Process in Landfill

By operating an anaerobic degradation experiment of municipal solid waste landfill, the effects of periodic leachate emission, rainfall infiltration and full leachate recirculation on biodegradation process in landfill were investigated. And the control measures of water migration in biogas resources landfill were discussed. The results show that: in the case of leachate emission, it is difficult to form the suitable environmental factors of Eh, pH and humidity for methanogens. Rainfall infiltration plays a faint adjective function on microbiology environment. Under the continuous erosion action of infiltration rainfall, cumulative net CODCr leaching load increases by 67.8%. Leachate recirculation causes its cumulative production and net COD Cr leaching load decreases by 70.9% and 88.5% respectively, which shows an obvious inhibited effect on microbial metabolism at 15±2℃. With the temperature increases to 35±2℃, methanogens-suitable environment forms rapidly, but it causes the rapid accumulation of NH4 +-N in leachate. The measures, such as reducing the infiltration volume, controlling recirculation temperature reasonably and dealing with nitrogen removal before recirculation, can significantly improve the harmless and resources level of landfill disposal.     

Fracture Geometry and Pressure Distribution in Fracture for Hydrofracturing

It is proved first that hydrofracture has a self-similar elliptic extending characteristic which is independent of the praseure distribution in fractures by the theory of fracture me-chanics in this paper.Based on this theory ,the approximative analytic solutions of pressure distribution in fractures have been put forward by fracture mechanics coupled with fluid mechanics.     

Migration and Distribution Rules of Tubifex in Filtration

The rules of migration and distribution regulation of tubifex in filtration were studied in the pilot system. Meanwhile, the influences of filtration rate, filtration cycle and backwashing on the worm’s migration and distribution in filtraion were discussed. The results showed that both the worm’s length and the particle size of filter media had obvious effects on migration and distribution: the smaller the worm’s length and the larger the particle size of filter media were, the stronger the worm’s migration capacity was. The filtration rate was the main migration power of tubifex in filtration, which meant high filtration rate could result in the worm’s leakage risk. Prolonging filtration cycle promoted migration, thus it is beneficial to control tubifex leakage risk that shortening filtration cycle. The remove of tubifex in a real sense can be realized by backwashing. And the stronger the backwashing intensity is, the better the removal efficiency is. Based on the experimental results, to control the worm’s leakage risk effectively, filtration rate and cycle would be lower than 9.4 m/h and 12 h, respectively. Backwashing intensity would be controlled about 25 L/s·m2, at which the obtained tubifex removal efficiency was 97.7%.     

施氮量对不同株型小麦品种叶型垂直分布特征的影响

在大田生产条件下,以紧凑型高秆品种宁麦9号和矮秆品种矮抗58、中间型品种扬麦12、松散型品种淮麦17为材料,测定并分析了3个施氮水平下不同生育时期的小麦冠层叶型特征,以及开花期小麦叶长和叶宽、单叶面积、茎叶夹角、分层叶面积指数和群体透光率的垂直分布特征。结果表明,小麦叶型特征存在显著的基因型差异,而施氮量的调控作用因叶型性状和生育时期不同而各异。叶片定形后,从植株基部向上,4个小麦品种不同叶位叶片单叶面积呈“升－降－升－降”的变化趋势,而茎叶夹角呈递减趋势。其最大分层叶面积指数所在的相对冠层高度为0.60。从冠层基部向上,群体透光率逐渐增加,符合二次多项式曲线。施氮提高了单叶面积,其中扬麦12和淮麦17的增加幅度较大。施氮提高了各叶位茎叶夹角,且对宁麦9号、淮麦17和扬麦12冠层下部茎叶夹角的调控作用大于冠层上部,而对矮抗58正好相反。施氮提高了各株型小麦品种的分层叶面积指数,降低了群体透光率,但过量施氮条件下,宁麦9号和矮抗58透光率的下降幅度小于扬麦12和淮麦17。各株型小麦品种群体透光率随累积叶面积指数的增加而递减。籽粒产量为N150 (150 kg hm^-2) > N225 (225 kg hm^-2) > N75 (75 kg hm^-2)。施氮显著提高了小麦品种穗数和收获指数,但对千粒重的影响不显著。穗粒数以高氮处理最高,低氮处理其次。籽粒产量、千粒重、穗数、穗粒数和收获指数在4个株型品种间差异显著,籽粒产量为矮抗58 > 宁麦9号 > 扬麦12 > 淮麦17,穗数和穗粒数是造成籽粒产量差异的主要原因。     

Prediction and Analyses of Residual Chlorine Based on Support Vector Regression in Urban Water Distribution System

Support vector regression(SVR) algorithm is an application of structural risk minimization principle in function regression.In this paper,a residual chlorine prediction model based on SVR is established by using the data of manual sampling residual chlorine of water distribution system in a certain city in the north of China.SVR model is compared with the artificial neural network and multivariate linear regression.The result shows that SVR model has better generalization ability for small samples,the predicted average relative error of all monitoring points is 1.80%~8.73%,and can achieve unique and globally optimal solutions.It is practical and can solve the problem for small samples of residual chlorine when the fit precision of model is good but the predicted effect is worse.     

固相萃取-气相色谱法检测八种有机磷农药的方法及条件优化

通过综合运用固相萃取-气相色谱联用技术,对八种具有代表性结构的有机磷农药敌敌畏、氧化乐果、甲胺磷、乐果、马拉硫磷、毒死蜱、对硫磷、甲基对硫磷的同时检测方法进行了探索和优化。方法检测限为1.1~2.5ug/L,线性范围为0.1~4mg/L,相对标准偏差为2.0~7.4%,回收率为69.1%~108.2%,完全满足农残检测要求。     

Investigation on the Pressure Head of Water Supply System with Head Tank

The water supply system with pump-head tank joint water supply is a mature technology widely used in high-rise buildings. In recent years, with widespread of new type pipe material and decoration of buildings, there is insufficient pressure head of water supplied at top floors in high-rise buildings. In this paper from the experience in engineering practice the reason for this problem and its countermeasures are investigated, then some suggestions are given.     

施肥对玉米田植物线虫群落组成及垂直分布的影响

为了明确玉米田植物线虫群落组成和垂直分布,于2007年采用蔗糖梯度离心法对80份土样进行分离鉴定,共鉴定出13个植物线虫属,玉米田不同施肥方式下植物线虫大部分为共有属。化肥配施有机肥区有1个特有属为拟毛刺属(Paratri-chodorus),化肥区有1个特有属为小环属(Cri-conemella),无肥区没有特有属。玉米田植物线虫主要集中在0~40cm土层,其中,玉米田单施化肥和无肥处理植物线虫密度在20~30cm土层达到最大,然后随深度的增加逐渐下降,化肥配施有机肥处理植物线虫数量在10~20cm土层达到最大值,30~40cm土层又达到一个峰值然后下降。     

10种绣线菊DNA的提取及RAPD反应体系的优化

旨在筛选出绣线菊属 RAPD 反应的最佳体系,为绣线菊属植物种质资源遗传多样性和亲缘关系的研究奠定基础.试验以 10 种绣线菊属植物为材料,采用改良 CTAB 法进行冬芽和嫩叶的总 DNA 提取并对影响 RAPD 扩增效果的因素进行优化.通过单因素优化筛选出最佳的 20μl 反应体系10×Taq buffer 2μl,Taq 酶 1.0U,0.15mmol/L dNTP,DNA 2ng/μl,引物 0.21μ mol/L,Mg2 2.0mmol/L;反应程序94℃预变性 4min,然后进行 40 个循环94℃变性 45s,37℃退火 1min,72℃延伸 1min.最后72℃延伸5min,4℃终止反应.结果发现,采用改良 CTAB 法所提取绣线菊冬芽的 DNA 达到 RAPD 反应的要求.筛选体系扩增出清晰稳定的多态性条带,可用于对绣线菊属遗传育种方面的研究.     

栽培技术优化对冬小麦根系垂直分布及活性的调控

为探索优化小麦根系构建,促进小麦根系功能发挥,以达到小麦高产高效的栽培技术,于2012—2013和2013—2014年度小麦生产季,通过大田试验,比较研究了鲁原502在旋耕-基肥撒施(RT-SF),深翻-基肥撒施(PT-SF)和苗带旋耕-间隔深松-分层深施肥(SRT-SS-DT)3种栽培技术下产量及其构成,研究麦田0~90 cm内不同土层根系形态分布及生理特性的差异。与RT-SF和PT-SF处理相比,SRT-SS-DT处理显著提高了小麦的千粒重及单位面积穗数,使最终产量提高了3.96%~13.29%。SRT-SS-DT处理促进了小麦根系生长发育,拔节后15~60 cm土层内的根长密度和根干重密度、30~75 cm土层内根系总吸收表面积和活跃吸收面积较其他处理显著提高,尤其是在施肥层(15~30 cm土层)。开花后20 d,15~30 cm土层SRT-SS-DT的根系总吸收表面积和活跃吸收面积较RT-SF提高了66.3%和56.5%,较PT-SF提高了75.9%和59.8%。SRT-SS-DT增强了15~90 cm土层的根系活力,同时减缓了生育后期根系活力的下降,开花期至花后20 d,15~30 cm土层根系活力下降值在SRT-SS-DT处理下较RT-SF和PT-SF降低了28.5%和14.9%。此外,在花后20 d,SRT-SS-DT处理小麦15~90 cm土层根系表现较低MDA含量和较高SOD活性,尤其是15~30 cm土层,根系SOD活性分别比PT-SF和RT-SF处理高20.6%和10.9%。15~90 cm土层根系活力和根干重占比与小麦产量呈显著正相关。结果表明,通过对苗带旋耕、间隔深松和分层深施肥等栽培技术的集成和优化,可以有效扩展深层土壤根系的分布,提高深层土壤根系的活性,尤其是施肥层,有助于小麦产量提高。     

Investigations of Distribution System Planning of Loop Configurations Using a Genetic Algorithm

The distribution system planning is performed with a loop configuration constraint from scratch.With Evolutionary Algorithm,a sample distribution network is designed with a loop configuration,in which the system is operated as radial configuration.It firstly introduces the mathematical model for distribution network planning,then the application of Evolutionary Algorithm for the planning of distribution network.By using the theory mentioned above, Visual C++ is applied to develop the distribution network optimization software.Finally with the optimization process of 17 nodes system being showed,the presented algorithm's utility and validity is verified.     

水稻梯田土壤速效氮、磷、钾的迁移与分布特征研究

研究水稻梯田氮、磷、钾速效成分迁移与分布规律,为实现精准配方施肥提供依据。选择白石村10个有水稻梯田分布的村民小组,每个村民小组为一个采样区,按照水流路径,每个采样区梯田分成6层,每层采用“S”形布点法采集5个土样,分别测定土壤的碱解氮、速效磷和速效钾含量,并建立与梯田层次间的函数关系式,研究其横向迁移分布情况与规律。结果表明：白石村土壤主要养分平均含量：碱解氮103.3±13.67 mg/kg、速效磷42.84±5.42 mg/kg、速效钾95.25±13.91 mg/kg,营养等级为中上;碱解氮、速效钾从上层梯田向下层梯田迁移,并有显著的指数回归趋势,平均相关系数分别为0.9719和0.9885,低洼地氮素含量偏高;速效磷纵向迁移不明显,但其含量与碱解氮含量呈负相关,拟合度为72.72%。白石村水稻梯田碱解氮、速效钾含量随着水流由上层向下层迁移,并具有明显的指数回归趋势;速效磷随水流迁移不明显,分布相对稳定,有富集倾向。     

应用数字图像技术估测冬小麦冠层生物量垂直分布特征的研究

用数字图像技术研究了冬小麦冠层生物量的垂直分布。表明用一行小麦图像比多行小麦图像估测小麦生物量能更好地满足线性回归关系,估测效果更佳,以此为基础进一步研究了分层像素数估测小麦冠层分层现存生物量和有效生物量的方法。利用分层绿色像素数(LGPN)指标定性分析了不同栽培模式下冬小麦群体有效生物量的垂直分布和动态变化,并确定了基于图像特征的可用于定量分析的小麦群体垂直分布指数（I）。     

利用CTAB/酸酚法提取棉花组织总RNA

通过借鉴植物DNA的CTAB提取方法,结合总RNA的LiCl沉淀法,摸索出一套适合于棉花组织总RNA提取和纯化的技术—CTAB 酸酚法。该方法与异硫氰酸胍法或冷酚法等相比具有更简便、得到的棉花组织总RNA完整性好和纯度高等优点。     

Density Distribution of Sand Packing in Vacuum Suction Molding Process and its Influential Factors

By means are measured of the direct observation of the packing behavior of sand in the vacuum suction molding process.The air and powder pressure,density distribution of sand core.The packing mechanisms are studied based on these experimental results.It found that the density distribution of sand core is elucidated by powder pressure theory,and the density distribution is decided by air flowing,sand chocking and shearing.