Composite hydrogeological investigation and characterisation methods applied at a nuclear power plant site in Taiwan

Drawing from the lessons learnt from the Fukushima nuclear disaster in Japan, the assessment of subsurface environmental hazard around nuclear power plants has emerged as a critical task. Consequently, aiming to better understand the possible environmental impact of radiation leaks into the groundwater, a prescreening programme was initiated in 2011 by the Taiwanese government. As part of this programme, this study conducted various borehole prospecting techniques to identify in situ hydrogeological characteristics at Chin‐Shan Nuclear Power Plant. Borehole electrical log, sonic log and temperature/conductivity log were conducted to explain the regional lithologic conditions and permeability of the formation. In conjunction with this, the interwell tracer and pumping test was carried out to simultaneously determine the hydraulic parameters. In our opinion, the implementation of such in situ end‐to‐end investigations is essential in interpreting in situ fluid and solute transport dynamics prior to programming any numerical scheme for early warning, vulnerability assessment and regular monitoring of a nuclear power plant site.     

Sparse optimization for inverse problems in atmospheric modelling

We consider inverse problems in atmospheric modelling represented by a linear system which is based on a source-receptor sensitivity matrix and measurements. Instead of using the ordinary least squares, we add a weighting matrix based on the topology of measurement points and show the connection with Bayesian modelling. Since the source-receptor sensitivity matrix is usually ill-conditioned, the problem is often regularized, either by perturbing the objective function or by modifying the sensitivity matrix. However, both these approaches may be heavily dependent on specified parameters. To ease this burden, we propose to use techniques looking for a sparse solution with a small number of positive elements. Finally, we compare all these methods on the European Tracer Experiment (ETEX) data where there is no apriori information apart from the release position and some measurements.     

A comparison between tracer gas and aerosol particles distribution indoors: The impact of ventilation rate,interaction of airflows,and presence of objects

The study investigated the separate and combined effects of ventilation rate, free convection flow produced by a thermal manikin, and the presence of objects on the distribution of tracer gas and particles in indoor air. The concentration of aerosol particles and tracer gas was measured in a test room with mixing ventilation. Three layouts were arranged: an empty room, an office room with an occupant sitting in front of a table, and a single‐bed hospital room. The room occupant was simulated by a thermal manikin. Monodisperse particles of three sizes (0.07, 0.7, and 3.5 μm) and nitrous oxide tracer gas were generated simultaneously at the same location in the room. The particles and gas concentrations were measured in the bulk room air, in the breathing zone of the manikin, and in the exhaust air. Within the breathing zone of the sitting occupant, the tracer gas emerged as reliable predictor for the exposure to all different‐sized test particles. A change in the ventilation rate did not affect the difference in concentration distribution between tracer gas and larger particle sizes. Increasing the room surface area did not influence the similarity in the dispersion of the aerosol particles and the tracer gas.     

化学示踪连通试验在矿井充水条件探查中的应用

为获取地下水流速和渗透系数等水文地质参数、查清含水层水力联系、查明矿井充水条件，在内蒙古某矿设计实施了化学示踪试验。通过对国内外化学示踪试验资料整理、统计分析，总结出化学示踪剂用量与投放距离、含水层性质的经验关系式，并对本次示踪剂用量做出了评价。同时，对试验中监测点水中均未出现Cl-浓度增高现象进行了科学解释，提出类似含Cl-示踪剂中的某些离子可能被地下岩层特定矿物质吸附时，只要化学试剂中的一种离子能达到试验效果，且具有成本低、易获取等特点，即可选择其作为示踪剂的观点。     

灰岩防治水的示踪试验方法研究

为探查潘北矿C3I组灰岩含水层与奥灰含水层之间的水力联系，以及F1，DFl断层的导、阻水性，用KI为示踪剂，开展示踪试验．结果表明，井田内奥灰水仅与C3 3下存在局部水力联系，与C3^1 C3^2灰岩含水层间无水力联系．在试验范围内，奥灰水通过不同尺度的通道对C3^3下含水层进行补给；露头灰岩区中F1，DF1均为导水断层，为A组煤层在开采过程中对底板灰岩水防治提供了科学依据．     

一种可调带宽算法在谐波检测中的应用

频率参数和带宽参数可调的自适应二维线性正弦跟踪滤波器,可较好地实现电流基波信号跟随与谐波检测,幅值和相角之间不存在非线性耦合关系,有利于参数调整;但算法中采用的误差值包含了高次谐波信号,影响了稳态精度,且极易受到系统中随机噪声干扰的影响;这里将误差信号作为自适应反馈量,通过该值的相干平均估计来调节算法的带宽参数;新算法克服了稳态误差偏大的缺陷,同时解决了带宽调整难题;负载电流实验分析结果表明该算法既能保证较快的动态响应速度,又能保证稳态精度。     

示踪气体法利用人体作为CO2释放源测量宿舍换气次数的方法探究

测量自然通风情况下学生宿舍的通风量对研究高校学生宿舍的室内空气品质具有重要意义。示踪气体法利用人体作为CO2释放源具有安全、方便、低成本等优点及大规模推广的可能性,但目前国内研究利用人体作为CO2释放源测量新风量的文献较少。因而,本文以高校学生宿舍单侧自然通风为研究对象,探究利用人体作为CO2释放源测量宿舍换气次数方法的可行性与可靠性。其一,验证了宿舍内CO2分布的均匀性,结果表明可仅在宿舍中心点处布置单个测点,其测试结果可代表宿舍内CO2的整体变化情况。其二,通过实验对人体CO2释放量的计算公式进行修正,得到了中国年轻女性CO2释放量的修正因子为0.75。其三,以SF6作为示踪气体进行实验对比,验证了以人体作为CO2释放源测量宿舍换气次数方法的可靠性。而后,本文分析了此方法的适用性,并指出以中国年轻女性作为CO2释放源,房间换气次数为1.5次/h时,人均最大可测房间体积约为10 m3。     

在线高分辨率示踪技术在重庆南山隧道水渗漏的应用研究

为研究南山隧道在岩溶槽谷区施工中产生的上覆岩体渗漏,根据试验区的水文地质条件,选择在地表涂山湖水库作为示踪剂投放点,在南山隧道涌水出口处作为接收点,采用荧光素钠作为示踪剂,进行在线高分辨率示踪试验。试验结果表明:涂山湖水库与南山隧道之间很可能存在三个相互并列的岩溶通道,水力连通时间约为142.0min。在线高分辨率示踪技术具有灵敏度高、取样时间密度小和不易受污染等特点。     

Design and verification of a model secondary clarifier for activated sludge

A model clarifier was designed using conventional methods for the surface calculation and an alternative pathway for the determination of the height and constructed accordingly. In addition, a new approach was used to evaluate the necessary scraper speed in comparison to full-scale clarifiers. Scaling effects were taken into account. The model clarifier was first tested by tracer experiments. Conductivity measurements were used for the clarification zone, whereas the thickening zone was tested using pyrene as an organic tracer compound. Finally, the behaviour of the model clarifier was compared with a full-scale settler. The results indicated that operation of the model clarifier was representative of full-scale behaviour, except for severe overloads. Hence, the small-scale clarifier qualified as a model for small-scale studies and could be installed on large-scale plants to monitor more transparently plant performance and sludge behaviour     

井间示踪测试中示踪剂用量计算方法

在参考国外井间示踪测试中示踪剂用量设计方法的报导及大庆油田井间示踪实践的基础上．以Brigham—Smith提出的水驱五点井网有效示踪物质用量计算方法为基础,提出了多层条件下的井网外的稀释修正,井网类型的修正、放射性示踪剂的衰变修正,并充分考虑环保因素和技术要求的示踪剂用量计算方法。同时也提出了商品纯度及有效示踪物质含量的示踪化学剂用量的计算方法。