Model-based direct search optimization of the broke recirculation system in a newsprint mill

This work is concerned with the dynamic modelling of the papermaking section of an integrated newsprint mill, and the subsequent application of two direct search methods in a proof-of-concept optimization study of broke recirculation strategies. The effect of the current broke recirculation policy on the mixed pulp properties at the paper machine headboxes was quantified using a dynamic simulation generating data for an objective function which reflected the rate of change in measurable (flow, consistency and temperature) and immeasurable (total dissolved solids and fibre length distribution) parameters. Genetic Algorithm and the Nelder–Mead simplex methods were then linked dynamically to the simulation and used to find improved ways of recirculating broke pulp. Specifically, the profile of the changes to the broke ratio was modelled using a quadratic function and a second-order transfer function, and the coefficients of these functions were optimized. The optimized broke recirculation resulted in a significant reduction in the value of the objective function, thus, suggesting that the fluctuations in the properties of the mixed pulp stream could be dampened and paper machine headbox stability improved. It is expected that this process enhancement strategy would contribute to an increase in production yield (via a reduction in the occurrence of paper machine breaks), and thus an overall reduction in the waste of materials and energy.     

修正SO2被动式采样器的感度

二氧化硫被动式采样器的采样感度受环境中湿度和硫酸盐等的影响，感度经修正后用于环境监测，其结果与紫外荧光法的相对误差小于１０％。     

毛细管柱顶空气相色谱法测定水中氯代苯研究

大口径毛细管柱顶空气相色谱测定水中氯苯类的方法 ,具有简便、快速、干扰少、灵敏度高等特点。 0 .2 5mL顶空气体进样 ,二氯苯和三氯苯的检出限为 0 .0 1～ 0 .1 μg/L ,灵敏度高于萃取法 40～ 1 0 0倍 ,更有利于地表水中氯苯类有机物的测定。     

感潮河段水环境容量计算方法探讨

对感潮河段水环境容量的污染物允许排放量的概念进行了分析，提出了基于动态的水质模型并利用计算机仿真和线性规划来进行感潮河段水环境容量计算的基本方法，该文着重介绍计算感潮河段水环境容量的技术方法，通过简化的计算实例对具体过程进行了说明，其原理成立，方法可行。     

静态顶空气相色谱法测定工业废水中的甲醛和苯酚

建立了静态顶空取样，气相色谱直接分析水产中甲醛和苯酚的方法。该方法有良好的重现性，甲醛、苯酚连续监测定6次的相对标准偏差分别为1．9％和4．7％，甲醛、苯酚的检测限分别为0.50mg/mL和0.30mg/mL，方法简便，快速，基底干扰小，适用于工业废水中甲醛和苯酚的同时，快速测定。     

区域污染物总量控制动态化管理技术应用研究

在对近十年江苏省扬州市社会经济环境方面几十个指标上万个数据进行科学分析的基础上,揭示出区域污染物总量控制与社会、经济、环境建设和发展相关联性,总量控制具有宏观性.区域污染物总量可纳入各级政府和相关部门行政首长政绩考核中.首次建立区域污染物总量控制考核指标体系水平等级的评定模式和动态管理的应用技术.该成果不仅为城乡可持续发展奠定了基础,也为区域实现污染物总量控制动态化、规范化管理提供技术支撑和启示.     

Wind tunnel attraction of grapevine moth females, Lobesia Botrana, to natural and artificial grape odour

Summary. Host plant volatiles which attract insect herbivores for egg-laying are of principal interest with respect to insect ecology and evolution. Direct applications concern population monitoring and control through behavioural manipulation. Identification of behaviourally active plant secondary metabolites is essential also for plant breeding for insect resistance. Grapevine moth females Lobesia botrana are attracted by upwind flight to green grape berries Vitis vinifera. The headspace of grape berries was collected on air filters. A solvent extract of these filters, released from a sprayer, attracted females in the wind tunnel. The results demonstrate that volatile cues mediate attraction of grapevine moth females to grape berries, and that headspace collections capture the essence of this odour signal. The air filter extracts were examined by gas chromatography coupled with electroantennographic detection, and the compounds eliciting a consistent antennal response in L. botrana females were identified by mass spectrometry. The headspace collection apparatus was calibrated for collection efficiency of the active compounds. Their recovery rate ranged from 35 % for methyl salicylate to 83 % for (E,E)-α-farnesene. A synthetic ten-component blend was then formulated. The blend consisted of compounds eliciting an antennal response, formulated in a blend ratio corrected for differences in collection efficiency. Subsequent wind tunnel tests showed that female attraction to this synthetic ten-component blend was not significantly different from attraction to grape berries, or to headspace collections of the same berries. At a release rate of 35 ng/h of the most abundant compound (E)-β-caryophyllene, 20 % of the test females approached the source of sprayed headspace collections and the ten-component synthetic blend, respectively. In comparison, 100 g of green berries, releasing the main compound (E)-β-caryophyllene at a rate of ca. 4.7 ng/h, attracted 10 % of the females by upwind flight followed by source contact.     

LES – DFSD modelling of vented hydrogen explosions in a small-scale combustion chamber

Accidental explosions are a plausible danger to the chemical process industries. In the event of a gas explosion, any obstacles placed within the path of the flame generate turbulence, which accelerates the transient flame and raises explosion overpressure, posing a safety hazard. This paper presents numerical studies using an in-house computational fluid dynamics (CFD) model for lean premixed hydrogen/air flame propagations with an equivalence ratio of 0.7. A laboratory-scale combustion chamber is used with repeated solid obstacles. The transient compressible large eddy simulation (LES) modelling technique combined with a dynamic flame surface density (DFSD) combustion model is used to carry out the numerical simulations in three-dimensional space. The study presented uses eight different baffle configurations with two solid obstructions, which have area blockage ratios of 0.24 and 0.5. The flame speed, maximum rate of pressure-rise as well as peak overpressure magnitude and timing are presented and discussed. Numerical results are validated against available published experimental data. It is concluded that, increasing the solid obstacle area blockage ratio and the number of consecutive baffles results in a raised maximum rate of pressure rise, higher peak explosion overpressure and faster flame propagation. Future model development would require more experimental data, probably in a more congested configuration.     

Application of a variable-speed ground-coupled liquid desiccant air-conditioner to multi-story office buildings in temperate regions

A new variable-speed ground-coupled liquid desiccant air-conditioner was proposed and applied to a multi-storey office building in a temperate city of Kunming in China. Dynamic system simulations were performed to compare its performance with a constant-speed ground-source heat pump system. It was found that the use of the new system for a single-floor office reduced the annual unbalanced load to the ground heat exchanger borefield by nearly 70% together with a borehole depth reduction of up to 30%. For the case of a multi-storey office building, the number of floors served could be increased by 144% together with a reduction of CO₂ emission by 43%. The results highlighted the merit of the new hybrid system with enhanced applicability when it was applied to a multi-storey office building in a temperate city.     

Emissions trading systems with cap adjustments

Emissions Trading Systems (ETSs) with fixed caps lack provisions to address systematic imbalances in the supply and demand of permits due to changes in the state of the regulated economy. We propose a mechanism which adjusts the allocation of permits based on the current bank of permits. The mechanism spans the spectrum between a pure quantity instrument and a pure price instrument. We solve the firms׳ emissions control problem and obtain an explicit dependency between the key policy stringency parameter—the adjustment rate—and the firms׳ abatement and trading strategies. We present an analytical tool for selecting the optimal adjustment rate under both risk-neutrality and risk-aversion, which provides an analytical basis for the regulator׳s choice of a responsive ETS policy.