A low cost method to detect polluted surface water outfalls and misconnected drainage

Sewer misconnections lead to discharge of wastewater direct to rivers and streams. They are difficult to detect due to their intermittent discharges and the wide range of compounds which can be discharged. Optical brighteners are strong indicators of the presence of sewer misconnection discharge in surface water sewers, representative of many components of misconnections, and easily identified. The authors have developed and tested a promising method to identify optical brighteners in sewer systems using inexpensive passive samplers and a simple analysis method. The method is used to identify large areas of four sewer systems which are polluted with misconnection discharge. Limited validation shows that the method successfully indicated diffuse pollution in the surface water sewer system.     

A novel method to model trees for building daylighting simulation using hemispherical photography

The ability to simulate the effect of trees on natural light performance in buildings is contingent upon accurate simulation of light passing through the canopy. Accurate simulations require some assumption of leaf angle distribution (LAD) to compute canopy gap fractions. The ellipsoidal LAD can very closely approximate real plant canopies. The method requires calculation of leaf area density from observed distribution of gap fraction as a function of zenith angle. Two sets of Neem trees were studied (small and large). Hemispherical image acquisition and analysis for both groups was carried out to measure gap fractions. The results helped to develop a 3D tree model that was used to simulate the effect of tree interception of daylight. The illuminance levels were simulated under the tree model and the output results were validated against actual measurements using MBE and RMSE techniques (small trees: MBE = 0.33, RMSE = 0.20; large trees: MBE = 9.68, RMSE = 2.02).     

反射波法检测水泥搅拌桩的应用

结合工程实例,对反射波法应用于水泥搅拌桩的理论基础、可行性、实际应用与可靠性进行了分析,指出只要选择合理,处理得当,在满足一定的条件下,利用反射波法检测水泥搅拌桩的桩身完整性是可行的,同时对反射波法检测水泥搅拌桩的局限性进行了探讨.     

混凝土结构雷达检测中的钢筋相互干扰研究

探地雷达目前已被广泛地应用于土木工程领域,但其在钢筋混凝土结构中的应用并不多,主要的原因是混凝土内配筋复杂,相邻钢筋对雷达波有很大的干扰,使雷达图像难以辨识。为更好地识别复杂配筋下的雷达图像,找出其雷达图像特征,研究了各种相邻钢筋的雷达图像并得出了一些对钢筋混凝土的雷达检测有益的结论。     

摄影探测混凝土表面微裂缝温度场的新方法

本文在对有缺陷混凝土试件温度场进行研究的基础上，通过摄影，摄取表面的含水量图像以及不同时刻含水量的变化图像，探测用灯光照射而肉眼难于观察的裂纹。并利用ANSYS5．6软件对其试验进行计算，并对结果进行了比较分析。     

灌砂法检测路基压实度技术要点探讨

介绍了灌砂法的基本原理及适用范围,对量砂的选择与标定进行了研究,从选点及检测频率、试坑开挖、含水率测定等方面提出了灌砂法检测路基压实度的技术要点,以达到提高测试结果精度的目的。     

Ground penetrating radar (GPR) study to detect seepage pathways in the Ajanta Caves in India

The present study used the ground penetrating radar (GPR) tool to decipher the presence of fractures which may be possible pathways for seepage into the Ajanta Caves in India. GPR data were collected by 40- and 200-MHz antennas from Geophysical Survey Systems, Inc. (GSSI). The data were edited and processed using the RADAN 6.5 software. The processed data indicate the presence of fractures of varying orientation in the basaltic formations. The study shows high reflection zones indicative of fractures as well as strong absorbance zones which may be a homogeneous zone without any fractures.     

回弹法检测混凝土强度的探究

从混凝土本构关系及强度与硬度的关系两方面,探讨了回弹法检测混凝土强度中,回弹值—碳化深度—强度这种推断方法的不准确性,并指出如果回弹法测量结果离散性较大时,应选择其他更合适的方法进行混凝土强度测试。     

高密度电法探测地下采空区应用研究

指出地下采空区引起的地面沉陷是工程建设的隐患,阐述了高密度电阻率方法探测地下采空区的应用方法,通过工程实例证明,该方法可有效地查明地下采空区的埋深及分布范围,为相关的设计提供可靠依据.     

EH4和纳米瞬变电磁法及激发极化联合探测断层构造

以某工程为例,使用EH4大范围探测查明了断层的大致位置和产状,采用纳米瞬变电磁在断层的大致位置进行详查,确定了断层的准确位置及产状,并根据极化率推测了断层富水性,指出EH4、纳米瞬变电磁法和激发极化联合探测断层的构造具有可行有效性。     

用低应变反射波法检测搅拌桩桩身完整性探讨

结合反射波法的基本原理,阐述了低应变反射波法检测搅拌桩的方法,并对水泥土搅拌桩桩身完整性检测方面进行分析,最后得出低应变反射波法检测水泥土搅拌桩还处于探索阶段,还需继续进行探讨的结论。     

Fish bile used to detect estrogenic substances in treated sewage water

Endocrine disrupting effects on fish associated with sewage treatment effluents have been demonstrated in several studies. To investigate if the effluents from two modern Swedish sewage treatment plants contained estrogenic substances, juvenile rainbow trout were exposed to sewage water before and after the last treatment step which is a sand filter. As a biomarker for estrogenic effect, vitellogenin was analysed in the blood plasma of the exposed fish. To identify substances possibly responsible for the effect, bile fluid from the exposed fish were analysed with GC/MS. Elevated levels of vitellogenin were only seen in the fish exposed at one of the sewage treatment plants, the one with shorter residence time in the biological treatment steps, which suggests that the residence time is of importance for the ability to reduce the amount of estrogenic substances in the sewage water. The highest elevation of vitellogenin was seen in the fish exposed to water before the sand filter, which indicates that the sand filter contributes to further reduction of estrogenic substances in the sewage water. In bile from the same group of fish, considerably higher concentrations of estrone, bisphenol A and 4-nonylphenol (4.0 microg/g bile, 23 microg/g bile and 24 microg/g bile, respectively) were observed compared to bile from control fish (<0.04 microg/g bile, 0.21 microg/g bile, and 3.5 microg/g bile, respectively). The more potent steroidal estrogens were suggested to be major contributors to the observed estrogenic effect, although xenoestrogens were detected at higher concentrations in the bile fluid.     

TSP法与探地雷达相结合在隧道超前地质预报中的应用研究

在当前隧道超前地质预报变得日趋重要的情况下,本文详细探讨了如何选择合理有效的预报方法。首先分析了我国现阶段所有的超前地质预报方法的优缺点,然后通过对比分析,提出了隧道的超前地质预报以TSP法长距离探测为主,同时有效地与探地雷达短距离探测相结合的预报方案。通过对邵阳．怀化高速公路多个隧道的应用研究,此方案取得了很好的预报效果,给施工单位提供了有效科学的指导。     

Development of a new biomonitoring method to detect the abnormal activity of Daphnia magna using automated Grid Counter device

The aim of the present study was to develop a biological early warning system (BEWS), equipped with six monitoring channels to individually observe the activity of Daphnia magna, using a digital 'Grid Counter', which would trigger an alarm within an appropriate time, and examine the functional performance of the newly developed BEWS for detecting unusual water quality. In order to detect the changes in the activity of D. magna, six relative activity parameter values (Z(a)) were computed from the 6 individual monitoring channels; with the activity data for D. magna calculated every 5 min. The Student's t-test was used to verify the difference between the mean value of the system in a steady state, as a control, and the exposure values during a sudden pollution event. The test results illustrate that the threshold value for the alarm can be at p=0.0093 for 3 consecutive detections. The time period, defined as the average time taken from the detection of hyper to retarded activity of the organism, for Cu concentrations of 50, 100, 200 and 400 ppb were 7.17+/-1.75, 3.94+/-2.02, 1.85+/-0.49 and 1.00+/-0.18 h, respectively. Based on the results of this study, it is proposed that p values from the t-test, with Z(a), are more accurate, stable and predictable parameters for the detection of chemical exposures than the other values, such as the swimming speed and trajectory, etc. Consequently, it would be possible to reduce the number of false alarms and achieve confidence for a system, with the ability of highly accurate detection, such as with the six-channel monitoring system developed in this study.     

Using reactive tracers to detect flow field anomalies in water treatment reactors

The hydraulics of water and wastewater treatment reactors has a major impact on their performance and control. The residence time distribution as a measure for the hydraulics represents macroscopic mixing in an integrated way with no spatial information. However, with regard to optimal sensor location for process control and for process optimisation measures, spatial information about macro-mixing is helpful. Spatially distributed measurements of reactive tracers can provide this information. In this paper we generally discuss how reactive tracers can be used to detect and characterize distinct large scale flow structures. It is shown that tracer substances are particularly suited if their reaction time scale is similar to the time scale of the large scale flow structure. For nitrifying activated sludge systems, ammonium is identified to be a suitable tracer. In a comprehensive experimental study at a real aeration tank, two distinct large scale flow features were identified by distributed ammonium measurements. Flow velocity measurements using acoustic Doppler velocimetry clearly supported the nature of these flow field anomalies. Ion-selective electrodes are a well suited device for ammonium measurements providing the temporal resolution that is needed for such an analysis.     

高密度电法探测未知目标体的技术及其效果

高密度电阻率法在各个领域得到了广泛的应用,并取得了良好的效果。本文主要说明了高密度电阻率法探测地下未知目标体的工作方法和各种可能遇到的问题及解决方案,包括线路连接,测线布置等方面,以及资料处理的细节问题。高密度电法不同装置具有不同的特点,这里结合高密度电阻率法数据采集过程中的各种因素进行了综合阐述,通过实例说明了高密度电法探测未知目标体的装置特点及其适用领域。     

红外热成像法在碳纤维粘贴质量检测中的应用

碳纤维施工质量的检测评估是保证其有效工况的一个重要手段。检测方法的有效性、覆盖性决定了对整体质量的评价。现有的国家验收规范在具体检测操作中,存在着一定的不足之处。本文提出了不同于现有规范的检测方法,将红外热像法引入到检测工作中,并验证了该方法的可操作性。     

Errors in bound water measurements using centrifugal settling method

Centrifugal settling method (CSM) is commonly used to estimate the bound water content in sludges. The sludge sediment matrix should be purely plastic for accurate measurements to the bound water content. This communication, however, addressed for the first time that, owing to the inhibited elasticity of the sludge matrix, sediment height rebound was commonly observed for the flocculated sludge. Also, different sludges could have distinct elastic responses after centrifugation. There existed no simple correlation to incorporate the elastic rebound of sludge sediment in bound water measurement. The possible errors incorporated into CSM for measuring bound water contents were highlighted.     

钻芯法检测超长龄期结构混凝土强度工程实践

为了在搁浅近十年的某超长龄期结构物上再加4层框架结构，介绍了用破损检测法-钻芯法检测工程框架梁、板、柱混凝土强度的方法，提供了一份较真实，可靠的检测数据。