Aliphatic and polycyclic aromatic hydrocarbons in the Xihe River, an urban river in China's Shenyang City: distribution and risk assessment

The characteristics of petroleum hydrocarbons and the risks they pose to the ecosystem were studied in the Xihe River, which is an urban river located in Shenyang, China. High levels of aliphatic hydrocarbons (AHc) and polycyclic aromatic hydrocarbons (PAHs) were observed in the river due to the discharge of wastewater from industrial and municipal facilities for a long period of time. High-molecular-weight hydrocarbons, including unresolved complex mixtures (UCM) of n-alkanes between n-C16 and n-C32 and of PAHs with four to six rings, were the dominant hydrocarbons in the river, particularly in suspended particulate matter (SPM) and sediments. The AHc was mainly from petrogenic sources, whereas PAHs was from both pyrolytic and petrogenic source inputs. Our results suggest that there is a high risk of toxicity for the soils and groundwater of the study area. The overall toxicity in the sediments can be described using the toxic equivalent (TEQ) of dibenzo[a,h]anthracene (DBA) based on benzo(a)pyrene (TEQ(BaP)) and dioxins (TEQ(TCDD)) toxic equivalent concentrations. The TEQ values for benzo(a)pyrene (TEQ(BaP)) and dioxins (TEQ(TCDD)) presented a consistent assessment of sediment PAHs.     

GenCLOn: An ontology for city logistics

City logistics is a discipline specialized to cope with the sustainability problems encountered in urban freight transport. A key characteristic of it is the heterogeneity of the stakeholders involved. Besides the traditional logistics actors such as shippers, carriers and receivers that share consistent interests (i.e. price and quality), city logistics highly respect the interests of public administrators and citizens that care more about the social welfare. To reach an optimal balance between private and public benefit, it is necessary to understand and in turn forecast the behavior pattern of different groups. In recent years, agent-based modeling has been practiced as an unconventional tool to fulfill this task for its strong capability on capturing the dynamic behavior of individual stakeholders and their interconnections. Referring to other domains (e.g. energy system) where the application of agent-based modeling is relatively mature, a following urgency is to achieve interoperability and in turn reusability between models via introducing formal ontology as a shared template with which developers can standardize their models. This paper introduces an initiative of developing an ontology that formalizes the domain knowledge of city logistics.     

基于RFPA2D的含裂隙灌浆帷幕体渗透损伤演化规律

以某石灰石矿涌水治理工程为背景,基于RFPA~(2D)-Flow软件,建立不同加载方案下的含45°狭长椭圆裂隙的灌浆帷幕体二维平面应变数值模型,分析了轴压、围压及渗透水头差等因素对含裂隙灌浆帷幕体作用的损伤演化规律。结果表明:在轴向加载作用下,裂隙灌浆帷幕体的裂纹发生在裂隙尖端附近,且裂隙倾角与初始裂隙呈垂直扩展、延伸直至贯通破坏,破坏形式呈径向拉裂破坏;在围压加载作用下,裂隙灌浆帷幕体的裂纹萌生同样发生在裂隙尖端附近,但围压加载的破坏裂隙是沿轴向扩展、延伸贯通的;渗透水头差对裂隙灌浆帷幕体的水压致裂形式与轴向加载的形式较为相近,都是径向贯通破坏,不同之处在于渗透水头差造成的破坏呈现为初始裂隙范围内径向粉碎性贯通破坏。     

高河能源高瓦斯综放工作面瓦斯防控体系研究

为解决高瓦斯综放工作面瓦斯超限难题,针对高河矿W1309综放面实际地质条件和开采技术水平,在分析W1309综放面双U型通风系统的基础上,结合Y型通风方式在防治综放面瓦斯超限的优势,提出“Y型通风+高抽巷”的工作面瓦斯防控模式。为充分发挥走向高抽巷的作用,运用Fluent软件对高抽巷不同垂距、不同平距下Y型通风工作面瓦斯分布规律进行数值模拟。结果表明：当高抽巷布置于煤层底板之上30m,与回风顺槽平距为25m的裂隙带中时,瓦斯抽采效果最好,抽采纯量达到18.52m_³/min,抽采浓度最高,可达8.11%,且上隅角瓦斯浓度最低0.61%。通过现场监测记录数据,得出现场数据与模拟值基本吻合,验证了数值模拟结果的可靠性,为工作面瓦斯防控体系的升级提供了理论指导。     

AXIAL HEAT CONDUCTION MODEL TO PREDICT MAXIMUM HEAT REMOVE OF MINIATURE HEAT PIPE BASED ON GREY MODEL THEORY

Computer chip is always accompanied by the increase of heat dissipation and miniaturization.The miniature heat pipes are widely used in notebook computer to resolve the heat dissipation problems.Maximum heat removed model of miniature heat pipes building by grey model is presented.In order to know the foundation for modeling,the smooth grade of error examination is inquired and the accuracy of grey relational grade is verified.The model can be used to select a suitable heat pipes to solve electric heat problems in the future.Final results show that the grey model only needs four experiment data and its error value is less than 10％,further,it is better than computational fluid dynamics (CFD) model.     

Distribution, partitioning and sources of polycyclic aromatic hydrocarbons in Daliao River water system in dry season, China

Eighteen polycyclic aromatic hydrocarbons (PAHs) were analyzed in 29 surface water, 29 suspended particulate matter (SPM), 28 sediment, and 10 pore water samples from Daliao River water system in dry season. The total PAH concentration ranged from 570.2 to 2318.6 ng L(-1) in surface water, from 151.0 to 28483.8 ng L(-1) in SPM, from 102.9 to 3419.2 ng g(-1) in sediment and from 6.3 to 46.4 microg l(-1) in pore water. The concentration of dissolved PAHs was higher than that of particulate PAHs at many sites, but the opposite results were generally observed at the sites of wastewater discharge. The soluble level of PAHs was much higher in the pore water than in the water column. Generally, the water column of the polluted branch streams contained higher content of PAHs than their mainstream. The environmental behaviors and fates of PAHs were examined according to some physicochemical parameters such as pH, organic carbon, SPM content, water content and grain size in sediments. Results showed that organic carbon was the primary factor controlling the distribution of the PAHs in the Daliao River water system. Partitioning of PAHs between sediment solid phase and pore water phase was studied, and the relationship between logK(oc) and logK(ow) of PAHs on some sediments and the predicted values was compared. PAHs other than naphthalene and acenaphthylene would be accumulated largely in the sediment of the Dalaio River water system. The sources of PAHs were evaluated employing ratios of specific PAHs compounds and different wastewater discharge sources, indicating that combustion was the main source of PAHs input.     

Phosphorus sorption and fraction characteristics in the upper, middle and low reach sediments of the Daliao river systems, China

Stream sediments play an important role in the transport and storage of phosphorus in the stream ecosystems. This research investigated the sorption and fraction of P in the sediments of a long-term seriously contaminated river, the Daliao river system, using isotherm sorption and selective sequentially extraction tests. Results indicated that the total content of P in the sediments was 479–1202 mg kg⁻¹, depending on iron content in the sediments. The content of potential bioavailable P, including soluble and loosely bound P, Al bound P, Fe bound P, and reductant soluble P was only 10–20% of total P in the sediments of the Hun river and Taizi river, while it was 40–55% in the sediments of the Daliao river, the downstream of the river system. Equilibrium phosphorus concentration without net P sorption (EPC₀) was from 0.05 to 0.54 mg L⁻¹, with an increasing trend from upstream to downstream, indicating increasingly release potential. On the other hand, the upstream sediment generally sorbed more P than the downstream sediment for each river at the same equilibrium P concentration. The binding energy constant of P on the strong sites of the sediments generally decreased from 2.24 to 2.65 L mg⁻¹ at upstream to 0.41 L mg⁻¹ at downstream or estuary, suggesting that the strong binding sites have been occupied and partly saturated by the phosphate added by point and diffuse sources along the river. On the other hand, molar ratio of Fe to TP contents in the sediments showed sorption capacity of the sediments to P might be under-saturated. The added or sorbed P by the isotherm test was primarily bound to Fe oxides and secondly to Al oxides. Long-term pollution of the river lead to the decrease of P sorption capacity of the river sediment and the increase of P release potential.     

气泡效应对地震资料的干扰及压制方法

海洋地震勘探中,空气枪激发后会产生气泡效应,气泡效应产生的子波属于干扰波,具有周期性、低频率的特点。设计合理的枪阵配置,气泡效应可以得到一定的压制,但无法完全消除,对地震资料影响较大。根据气泡干扰与有效波在频率、频次间的差异,重点介绍了震源设计压制气泡的方法及效果,子波处理及噪音压制气泡干扰的方法,并展示了各自的效果。结果表明,子波法对深水资料的气泡压制效果较好,对浅水资料,将子波处理与噪音压制这两种方法结合使用效果更佳。     

An electrodeposition approach to metal/metal oxide heterostructures for active hydrogen evolution catalysts in near-neutral electrolytes

Neutral water splitting is attractive for its use of non-corrosive and environmentally friendly electrolytes. However, catalyst development for hydrogen and oxygen evolution remains a challenge under neutral conditions. Here we report a simple electrodeposition and reductive annealing procedure to produce a highly active Ni-Co-Cr metal/metal oxide heterostructured catalyst directly on Ni foam. The resulting electrocatalyst for hydrogen evolution reaction (HER) requires only 198 mV of overpotential to reach 100 mA/cm² in 1 M potassium phosphate (pH = 7.4) and can operate for at least two days without significant performance decay. Scanning transmission electron microscopy coupled with electron energy loss spectroscopy (STEM-EELS) imaging reveals a Ni-Co alloy core decorated with blended oxides layers of NiO, CoO and Cr₂O₃. The metal/metal oxide interfaces are suggested to be responsible for the high HER activity.

     

Sb(Ⅴ)在高岭土表面的吸附:pH、离子强度、竞争性离子与胡敏酸的影响

调查了在不同的pH、离子强度、胡敏酸和竞争性离子存在的条件下Sb(Ⅴ)在高岭土表面的吸附行为.pH对Sb(Ⅴ)在高岭土表面的吸附行为影响显著,pH在3～8之间时,随介质pH的升高,Sb(Ⅴ)的吸附减弱;离子强度、胡敏酸的存在对吸附的影响均不显著;PO3-4 的存在对Sb(Ⅴ)在高岭土表面的吸附有明显的抑制作用.