天山冰雪圈地貌过程和自然灾害

天山山地地貌过程受水热分布和地形的影响具有明显的水平和垂直分异性。因此，由地貌过程引起的自然灾害也具有区域分异和垂直分异性。天山冰雪圈指的是冰缘和冰川地貌景观带，其中的过程与自然灾害同样具有区域性和垂直性的分异。目前发生在天山冰雪圈的主要灾害为雪崩、泥石流、洪水和崩塌。本文主要讨论它们的形成条件、过程特征和成灾规律，并提出减灾的初步措施。     

Urinary concentrations of phenols, oxidative stress biomarkers and thyroid cancer: Exploring associations and mediation effects

Phenols have been shown to influence the cellular proliferation and function of thyroid in experimental models. However, few human studies have investigated the association between phenol exposure and thyroid cancer, and the underlying mechanisms are also poorly understood. We conducted a case-control study by age- and sex-matching 143 thyroid cancer and 224 controls to investigate the associations between phenol exposures and the risk of thyroid cancer, and further to explore the mediating role of oxidative stress. We found that elevated urinary triclosan (TCS), bisphenol A (BPA) and bisphenol S (BPS) levels were associated with increased risk of thyroid cancer (all P for trends < 0.05), and the adjusted odds ratios (ORs) comparing the extreme exposure groups were 3.52 (95% confidence interval (CI): 2.08, 5.95), 2.06 (95% CI: 1.06, 3.97) and 7.15 (95% CI: 3.12, 16.40), respectively. Positive associations were also observed between urinary TCS, BPA and BPS and three oxidative stress biomarkers measured by 8-hydroxy-2′-deoxyguanosine (8-OHdG), 8-iso-prostaglandin F_2α (8-isoPGF_2α) and 4-hydroxy-2-nonenal-mercapturic acid (HNE-MA), as well as between urinary 8-isoPGF_2α and HNE-MA and the risk of thyroid cancer. Mediation analysis showed that urinary 8-isoPGF_2α mediated 28.95%, 47.06% and 31.08% of the associations between TCS, BPA and BPS exposures and the risk of thyroid cancer, respectively (all P < 0.05). Our results suggest that exposure to TCS, BPA and BPS may be associated with increased risk of thyroid cancer and lipid peroxidation may be an intermediate mechanism. Further studies are warranted to confirm the findings.     

Organoiodines in effluents of a shale-fracturing wastewater treatment plant

Environmental Chemistry Letters - Shale gas extraction is increasing worldwide in the context of the energy crisis, yet the associated pollution by this industrial activity is poorly known. Here we...     

Effects of metal pollution in the monosodium glutamate production effluent on full exploitation and biological treatment

Monosodium glutamate (MSG) effluent was sampled from three MSG mills and 21 metal elements were measured with a inductively coupled plasma (ICP) Spectrometer. The total metal concentration of each MSG wastewater sample was 19192, 3190 and 3161 mg/L respectively. Compared with the water quality standard issued by the Chinese Government and the World Health Organization (WHO), some values were found to exceed the standards. The 24hr‐LC₅₀, 48hr‐LC₅₀, 72hr‐LC₅₀ and 96hr‐LC₅₀ to the fish Ctenopharyngodon idellus were 6.9%, 3.2%, 2.5% and 1.4% MSG wastewater individually. The specific growth rate for photosynthetic bacteria (PSB) Rhodopseudomonas sphaeroides was inhibited by the metals in MSG wastewater. Therefor the MSG wastewater should not be discharged into drinking, irrigation and fishery water systems, moreover it cannot be treated by general biological processes efficiently. How to develop an effective biotechnique for the utilization of organic pollutants in MSG effluent will also be discussed in this paper.     

Synthesis of heterojunction photocatalysts composed of Ag 2 S quantum dots combined with Bi 4 Ti 3 O 12 nanosheets for the degradation of dyes

Environmental Science and Pollution Research - Facilitating the separation of photogenerated electron/hole pairs and widening the light-responsive region are crucial to enhance the overall...     

不同标准下外压筒体轻量化设计

LNG运输半挂车根据GB 1589-2016《汽车、挂车及汽车列车外廓尺寸、轴荷及质量限值》的规定最大允许总质量不能超过40t,轻量化LNG运输车是今后市场发展方向之一。LNG运输车外筒体由于受外压作用,往往通过设置较多加强圈来防止其失稳。在材质、直径、壁厚、长度均相同条件下的外筒体,按GB/T150《压力容器》、JB 4732《钢制压力容器》、ASME B&P Code VIII-2等不同标准下进行失稳计算,同种规格角钢圈数量大不相同,按ASME B&P Code VIII-2标准计算得出的角钢圈数量最少,轻量化程度更高,更具有市场竞争力。     

精对苯二甲酸生产企业挥发性有机物泄漏检测与排放估算

采用泄漏检测与修复(LDAR)技术分析了某精对苯二甲酸生产装置动静密封点的泄漏情况,共完成1 367个密封点的现场LDAR检测,测出28个泄漏点,总泄漏检出率为2.05%。其中储存单元的泄漏点数量较氧化单元和精制单元高,泄漏程度也较严重。泄漏点主要集中在法兰、开口管线和泵三类密封点;涉及轻液的泄漏密封点数量较多。依据LDAR检测结果,采用相关方程法估算设备动静密封点泄漏产生的挥发性有机物(VOCs)排放量约为4.999 t/a。法兰的VOCs泄漏排放量最大,约占63.89%,其次是泵和采样连接系统,占泄漏排放量的20.78%和7.89%。     

Influence of influent on anaerobic ammonium oxidation in an Expanded Granular Sludge Bed-Biological Aerated Filter integrated system

Shortcut nitrification-denitrification, anaerobic ammonium oxidation (ANAMMOX), and methanogenesis have been successfully coupled in an Expanded Granular Sludge Bed-Biological Aerated Filter (EGSB-BAF) integrated system. As fed different synthetic wastewater with chemical oxygen demand (COD) of 300–1200 mg·L^-1 and NH4+-N of 30–120 mg·L^-1 at the outer recycle ratio of 200%, the influence of influent on ANAMMOX in the integrated system was investigated in this paper. The experimental results showed that higher COD concentration caused an increase in denitrification and methanogenesis but a decrease in ANAMMOX; however, when an influent with the low concentration of COD was used, the opposite changes could be observed. Higher influent NH4+-N concentration favored ANAMMOX when the COD concentration of influent was fixed. Therefore, low COD/NH4+-N ratio would decrease competition for nitrite between ANAMMOX and denitrification, which was favorable for reducing the negative effect of organic COD on ANAMMOX. The good performance of the integrated system indicated that the bacterial community of denitrification, ANAMMOX, and methanogenesis could be dynamically maintained in the sludge of EGSB reactor for a certain range of influent.     

天津滨海湿地土壤有机碳储量及其影响因素分析

对天津滨海湿地的土壤有机碳(SOC)储量进行了研究. 结果表明:滨海湿地土壤表层(0～30 cm)w(SOC)为(8.55±3.98)g/kg,平均土壤有机碳密度为(4.70±1.91)kg/m2,低于全国平均水平. 从土地覆盖类型看,除林地外,滨海湿地土壤中w(SOC)也处于偏低水平. 滨海湿地的土壤中w(SOC)与土壤环境因子有显著相关关系,由此建立回归方程,认为土壤中w(黏粒)和pH是影响土壤中w(SOC)的最主要因素,二者可以解释71.8%的土壤有机碳分布情况. 提出对滨海湿地的改良建议,认为适当地进行人为管理和调控,对土壤环境的改善及土壤有机碳储量的增加有积极作用.      

高浓度废水可调式厌氧处理技术

以酒精发酵和有机化工混合废水为研究对象,通过对原厌氧工艺的改进,成功地研发了"可调式Ⅰ级全糟发酵/DDG+Ⅱ级UASB+Ⅲ级IC"厌氧工艺,实现了废水有机负荷和进入方式的随机调节。运行结果表明:新工艺运行稳定,有机负荷提高1倍,沼气产率提高39%~56%,厌氧阶段出水COD由原工艺的2000 mg/L降低到500 mg/L左右,COD去除率由93%上升到99%。