阿姆河流域耕地变化及水土匹配特征分析

基于中亚阿姆河流域4个分区1990—2015年间土地利用变化和水资源等数据,运用耕地变化速率、洛伦兹曲线和基尼系数法以及水土资源匹配系数对阿姆河流域耕地变化和水土匹配状况进行了综合分析。结果表明:1990—2015年阿姆河流域耕地以146.74 km²/a的速度在扩张,且各时期、各分区扩张的速度不同;在不考虑咸海来水不断减少、生态持续恶化的前提下,绿洲区匹配状况属比较公平和相对合理状况;阿姆河流域水土资源空间分布存在明显的错位现象;全流域生态用水被农业用水严重挤占,阿姆河流域灌溉面积、灌溉用水量成为影响咸海水量及面积变化的重要因素,是一种不可持续的用水方式。     

Enhanced anti-biofilm activity of facile synthesized silver oxide nanoparticles against K. pneumoniae

Journal of Inorganic and Organometallic Polymers and Materials - The silver oxide nanoparticle was successfully synthesized using floral waste by simple one pot, cost effective method. The complete...     

Water and Sediment Quality in Lakes along the Middle and Lower Reaches of the Yangtze River, China

Water and sediment samples were collected from 45 lakes along the middle-lower Yangtze River, China. Each lake was sampled seasonally, over a period of one year. Water quality variables and metals in sediments were measured. Lakes along the lowest part of the river, within the Yangtze River Delta, had highest nutrient concentrations and were eutrophic or hypereutrophic. Lakes displayed a gradient in many water chemistry variables, from the middle to the lower Yangtze River. Lakes of the Delta region had the highest conductivity, sulfate, turbidity, and Chl-a values, and the lowest dissolved oxygen concentrations. A number of lakes near urban areas in the study region also displayed similar conditions. Lakes polluted by heavy metals were found in the upper part of the lower Yangtze River and had high Cu, Cr, and Co concentrations in sediments. The mean I_geo (index of geoaccumulation) values for Cu, Cr, and Co classes ranged from 0 to 4, indicating moderate to heavy contamination, contributed mainly from untreated industrial waste water produced within the lake catchments. Lakes of the middle Yangtze River are generally in relatively better condition, except for those around urban zones, which experience higher nutrient and heavy metal loading. The spatial distribution of lake conditions in the area can be related to the policy of regional economic development. The Delta region in China is developed and includes such cities as Shanghai and Suzhou. Heavy industries have moved into the interior region of China too, and development of modern cities is now occurring under some level of environmental protection. Nevertheless, lakes in the central part are becoming seriously polluted with both heavy metals and nutrients because local authorities promote industrialization and urbanization to improve economic conditions, while often ignoring environmental protection. Pollution is increasingly occurring in upstream reaches, a tendency that will bring more environmental problems. Interior lakes of China require immediate attention to prevent further declines in water quality.     

A numerical study of natural convection heat transfer in a vertically eccentric spherical annulus

The results of a numerical investigation of the natural convection process between isothermal vertically eccentric spheres with hotter inner core, are being presented. The Grashof and the Prandtl numbers have been kept constant at 4×10⁴ and 10 respectively. Eccentricities varying from −0.75 to +0.75 have been studied. From the numerical solution, it is possible to explain the average results obtained previously for the regime where the steady crescent flow pattern exists. Negative eccentricities have been found to enhance convection while positive eccentricities have the reverse effect. Results also show that heat transfer actually increases slightly for very high positive eccentricities where conduction plays an important role.     

New unstructured mesh water quality model for coastal discharges

A new unstructured mesh coastal water and air quality model has been developed that includes species transport, nonlinear decay, byproduct formation and mass-exchange between sea and atmosphere. The model has been programmed with a graphical interface and is applicable to coastal seawater, lakes and rivers. Focused on species conversion and interaction with the atmosphere, the water and air quality model follows a modular approach. It is a compatible module which simulates distributions based on fluid dynamic field data of underlying existing hydrodynamic and atmospheric simulations. Nonlinear and spline approximations of decay and growth kinetics, byproduct formation and joint sea–atmosphere simulation have been embedded. The Windows application software includes functions allowing error analysis concerning mesh and finite volume approximation. In this work, an anoxic submerged process-water discharge has been simulated. An error analysis has been carried out by varying vertical meshing, time-steps and comparing results based on explicit and implicit finite volume approximation.     

Spectroscopic studies of CSA-doped poly[C-hydroxyl-(4-N-dimethylamino)phenyl]dithienylmethine and doping effects on ionic conductivity

Protonation of poly[C-hydroxyl-(4-N-dimethylamino)phenyl]dithienylmethine with (1S)-(+)-10-camphorsulfonic acid (CSA) induced a structural change on the pendant group of the polymer and resulted in the formation of a cationic quinoid iminium moiety. This chemical transformation changed the polymer from a non-conducting polymer into a semi-conducting polymer with the maximum ionic conductivity of 2 × 10⁻⁴ S cm⁻¹ at 10 mol% CSA-doping level. The polydithienylmethines doped with various CSA loadings were characterized by UV–vis-NIR, FT-IR and Raman spectroscopy. An ion-hopping mechanism was suggested as the conduction mechanism for this CSA-doped polymer.     

检测仪器及消解方式对罗布麻微量元素检测效果的影响

目的 探索罗布麻微量元素适宜的检测条件。方法 以新疆产罗布麻和白麻叶及其制品罗布麻茶为实验材料, 比较了电感耦合等离子体质谱法(inductively coupled plasma mass spectrometry, ICP-MS)和电感耦合等离子体原子发射光谱法(inductively coupled plasma atomic emission spectrometry, ICP-AES)2种仪器对其Li、B、Cr、Fe、Mn、Cu、Zn、Se和Sr 9种微量元素的检测效果, 同时对比了3种不同的湿法消解方式对检测结果的影响。结果 采用不同酸解液的3种湿法消解方法, 硝酸/过氧化氢消解液处理条件较温和, 元素损失量较少, 检测结果稍高于浓硝酸/高氯酸消解液处理的结果, 但所耗消解时间更长。对于易挥发元素Se, 选用酸性和氧化性较弱的硝酸/过氧化氢消解液更适宜。在本试验条件下, 罗布麻体内的Li和Cr 2种微量元素不宜采用ICP-AES仪器检测, 可选用ICP-MS, 而对于难电离元素Se则正好相反。结论 检测罗布麻微量元素含量时, 应根据待检测元素类型特征, 选择适宜的检测仪器。     

Application of simplified rapid equilibrium models in simulating experimental breakthrough curves from fixed bed biosorption reactors

A modelling approach for a fixed bed biosorption column is presented. The Advection–Dispersion–Reaction (ADR) equation has been applied as the basic modelling equation for the special case of Local Equilibrium (LE). The model implements the minimum parameters for describing a fixed bed biosorption column, employing the geometrical dimensions of the bed, the packing arrangement, the operating conditions of the system, and the sorptive characteristics of the biosorbent material. An apparent axial dispersion coefficient has been used as a key parameter of the model. The authors compare model predictions to selected examples of experimental biosorption breakthrough curves reported from pilot scale work. Although the main assumption of the model is that biosorption equilibrium is rapid, the use of an apparent overall dispersion coefficient makes the model applicable for the cases where mass transfer resistances are present in the liquid and solid phases.