COMPARISON OF STOCHASTIC AND DETERMINISTIC DYNAMIC PROGRAMMING FOR RESERVOIR OPERATING RULE GENERATION1

ABSTRACT: Two dynamic programming models — one deterministic and one stochastic — that may be used to generate reservoir operating rules are compared. The deterministic model (DPR) consists of an algorithm that cycles through three components: a dynamic program, a regression analysis, and a simulation. In this model, the correlation between the general operating rules, defined by the regression analysis and evaluated in the simulation, and the optimal deterministic operation defined by the dynamic program is increased through an iterative process. The stochastic dynamic program (SDP) describes streamflows with a discrete lag-one Markov process. To test the usefulness of both models in generating reservoir operating rules, real-time reservoir operation simulation models are constructed for three hydrologically different sites. The rules generated by DPR and SDP are then applied in the operation simulation model and their performance is evaluated. For the test cases, the DPR generated rules are more effective in the operation of medium to very large reservoirs and the SDP generated rules are more effective for the operation of small reservoirs.     

混合菌对石油的降解

从含油污水中分离得到4株能高效降解石油的微生物菌株(X2、X3、X4、X5),经鉴定,4株菌分别属于黄单胞菌属(Xanthomonas sp.)、动胶菌属(Zoogloea sp.)、芽孢杆菌属(Bacillus sp.)和邻单胞菌属(Plesiomonas sp.).通过观察4株菌在原油培养基中的生长变化过程,确定了其中的优势菌;并对4株菌进行复配实验以确定各株菌混合后的石油降解效果;用正交实验法确定达到最佳石油降解效果各菌的投加量;通过对残油的Gc-MS测定分析,确定各菌在降解石油时所起的作用.结果表明,混合菌株中菌X4为优势菌,且有高的降解效果(达68,60％),其它3株降解率不高的菌混合投加也能达到较高的降解效果(达63.17％),菌X4是混合菌株维持高降解率的关键;达到最佳降解效果的各菌投加量分别为0.1％、0.1％、0.5％、2.0％;菌X2和菌X3降解C12-C16直链烃和少量支链烃,菌X4和菌X5对C12-C22直链烃有好的降解效果.图2表4参10     

有机磷类杀螺增效剂在土壤中的吸附行为

通过测定16个有机磷类杀螺增效剂在安徽省宿县土壤中的有机硕吸附系数（Koc),研究了该类化合物的环境行为;并用碎片分子连接性指数（FMCIs)和线性溶剂化能参数（LSERs)结构描述符,与土壤有机碳吸附系数之间进行了定量结构-性质相关（QSPR）分析,所得到的两组预测方程,可用于该类化合物的生态风险评价。     

电解氧化法处理黄金冶炼厂选冶废水

采用电解氧化法处理同时含有高浓度氰化物与COD的黄金冶炼厂选冶废水,主要考查了外加电压、溶液pH、电解时间及极板间距等因素对氰化物和COD去除率的影响,充分利用原水中Cl^-的阳极氧化效应,深入探讨了电化学氧化过程及污染物氧化去除机理。结果表明,随着外加电压和电解时间的增大,氰化物和COD去除率逐渐增大。以石墨为阳极,钛合金为阴极,采用一阴两阳电解体系对废水进行氧化,当电压为4.5 V、初始pH为7、电解时间为3 h、极板间距为1.5 cm的条件下,总氰化物 (CN_T) 、COD、SCN^-及Cu的去除率最高可达99.6%、96%、99.9%与99.2%。电解过程中体系pH逐渐降低,电场作用下定向迁移至阳极附近的污染物去除主要归因于HClO及ClO^-的间接氧化作用,当pH大于5.0时以HClO的氧化为主,ClO^-的氧化为辅,而pH小于5.0时则主要是HClO的氧化。电解氧化过程中约有36.17%的Cu与SCN^-形成CuSCN沉淀而被除去,剩余的铜则扩散至阴极沉积析出。GC-MS分析表明,烷烃类、酯类、酮类等大分子的C=C键、酯基、羰基等化学键和官能团被氧化断链成小分子物质,随后继续被氧化为H₂O、CO₂和N₂。     

Preliminary shotgun glycoproteome analysis of N-glycosylation sites in serum proteins of ricin-intoxicated rats

In this study, the variations of serum glycoproteins after exposure to ricin toxin (RT) in Wistar albino rats are reported. For glycopeptide enrichment, Microcon YM-3 centrifugal filter device capture and micro-liquid chromatography (LC)–electrospray ionization (ESI)–tandem mass spectrometric (MS/MS) analysis were used; 74 trypsin-digested proteins were identified in the control group, and 58 in the RT-intoxication group. Additionally, 33 N-glycosides and 14 glycoproteins were identified in the control, and 50 and 21 in the RT-intoxication group.     

Detection and quantitation of trace levels of low molecular weight halocarbons (LMHs) associated with commercial sodium humate

Examination of vapor above commercial sodium humate and above 10wt% aqueous humate solution by gas chromatography (GC) revealed the presence of chloroform and trichloroethylene. Further examination of the aqueous humate by the purge and trap procedure confirmed the association of chloroform and trichloroethylene with the humate. GC/mass spectrometry analyses of methylene chloride extract of the humate established the association of LMHs with the humate. Improved headspace capillary GC technique showed that the humate contained not only chloroform, trichloroethylene but several other LMHs in the range 190 to 4000ng·kg^‐1.     

Potentiometric studies of mixed complexes of cobalt(II) and copper(II) with l‐Asparagine and adenine

A potentiometric titration technique has been used to determine the stability constants for the various complexes of Co(II) and Cu(II) with L‐asparagine and from DNA base, e.g. adenine. Stability constants of ternary systems have been evaluated by the method suggested by Irwing‐Rossotti. In addition, the conditional constants were calculated as a function of pH. The maximum values of the conditional formation constants were found to be in accordance with the mixed‐ligand complex formation constants in a determined pH region. Furthermore, the molar fractions of different species from mixed complexes were calculated by means of formation constants. The values of stability constants of mixed‐ligand complexes at 25°C are as follows: log K= 5.25 for Co(II)‐L‐asparagine‐adenine; log K= 9.30 for Cu(II)‐L‐asparagine‐adenine. The ionic strength was kept constant at I = 0.20 with NaClO₄.     

Effect of Planning for Connectivity on Linear Reserve Networks

Although the concept of connectivity is decades old, it remains poorly understood and defined, and some argue that habitat quality and area should take precedence in conservation planning instead. However, fragmented landscapes are often characterized by linear features that are inherently connected, such as streams and hedgerows. For these, both representation and connectivity targets may be met with little effect on the cost, area, or quality of the reserve network. We assessed how connectivity approaches affect planning outcomes for linear habitat networks by using the stock‐route network of Australia as a case study. With the objective of representing vegetation communities across the network at a minimal cost, we ran scenarios with a range of representation targets (10%, 30%, 50%, and 70%) and used 3 approaches to account for connectivity (boundary length modifier, Euclidean distance, and landscape‐value [LV]). We found that decisions regarding the target and connectivity approach used affected the spatial allocation of reserve systems. At targets ≥50%, networks designed with the Euclidean distance and LV approaches consisted of a greater number of small reserves. Hence, by maximizing both representation and connectivity, these networks compromised on larger contiguous areas. However, targets this high are rarely used in real‐world conservation planning. Approaches for incorporating connectivity into the planning of linear reserve networks that account for both the spatial arrangement of reserves and the characteristics of the intervening matrix highlight important sections that link the landscape and that may otherwise be overlooked. El Efecto de la Planeación para la Conectividad en Redes de Reservas Lineales     

基于CLUE-S和灰色线性规划的嘉兴北部土地利用优化配置研究

构建基于CLUE-S与灰色线性规划混合模型的土地利用优化配置方法,在导入区域政策、社会经济、生态目标和土地利用现状等条件下,进行土地利用数量结构与空间布局的统一优化,并以嘉兴北部地区为例进行实证研究,共设置现状趋势情景、规划目标情景和规划可持续情景这3种模拟情景.规划可持续情景侧重社会经济环境效益,故对建设用地快速增长和农用地持续减少起到明显调控作用,可实现生态敏感区环境和粮食安全的双重保护,是理想的土地利用优化方案.CLUE-S模型与灰色线性规划的耦合能够兼顾现状条件和区域发展目标,模拟土地利用的数量和空间变化,是解决土地资源优化配置问题的有效方法.     

Heavy metal contamination in the vicinity of an industrial area near Bucharest

BACKGROUND, AIMS AND SCOPE: Chromium enters into the aquatic environment as a result of effluent discharge from steel works, electroplating, leather tanning industries and chemical industries. As the Cr(VI) is very harmful to living organisms, it should be quickly removed from the environment when it happens to be contaminated. Therefore, the aim of this laboratory research was to develop a rapid, simple and adaptable solvent extraction system to quantitatively remove Cr(VI) from polluted waters. METHODS: Aqueous salt-solutions containing Cr(VI) as CrO4(2-) at ppm level (4-6 ppm) were prepared. Equal volumes (5 ml) of aqueous and organic (2-PrOH) phases were mixed in a 10 ml centrifuge tube for 15 min, centrifuged and separated. Concentrations of Cr(VI), in both the aqueous and organic phases, were determined by atomic absorption spectrometry. The effects of salt and acid concentrations, and phase-contact time on the extraction of Cr(VI) were investigated. In addition, the extraction of Cr(VI) was assessed in the presence of tetramethylammonium chloride (TMAC) in 2-PrOH phase. Effects of some other metals, (Cd(II), Co(II), Cu(II), Ni(II) and Zn(II)), on the extraction of Cr(VI) were also investigated. RESULTS AND DISCUSSION: The Cr(VI) at ppm level was extracted quantitatively by salting-out the homogeneous system of water and 2-propanol(2-PrOH) using chloride salts, namely CaCl2 or NaCl, under acidic chloride media. The extracted chemical species of Cr(VI) was confirmed to be the CrO3Cl-. The ion-pair complex extracted into the organic phase was rationalized as the solvated ion-pair complex of [2-PrOH2+, CrO3Cl-]. The complex was no longer stable. It implied the reaction between extracted species. Studies revealed that salts and acid directly participated in the formation of the above complex. Use of extracting agents (TMAC) didn't show any significant effect on the extraction of Cr(VI) under high salting-out conditions. There is no significant interference effect on the extraction of Cr(VI) by the presence of other metals. The Cr(VI) in the organic phase was back-extracted using an aqueous ammonia solution (1.6 mol dm(-3)) containing 3 mol dm(-3) NaCl. The extraction mechanism of Cr(VI) is also discussed. CONCLUSIONS: Salting-out of homogeneous mixed solvent of 2-propanol can be employed to extract Cr(VI) quantitatively, as an ion-pair of [2-PrOH2+ * CrO3Cl-] solvated by 2-PrOH molecules. Then, the complex becomes 'solvent-like' and is readily separated into the organic phase. The increase of Cl- ion concentration in the aqueous phase favors the extraction. The 2-PrOH, salts and acid play important roles in the extraction process. There is no need to use an extracting agent at a high salting-out condition. RECOMMENDATIONS AND PERSPECTIVES: Chromium(VI) must be quickly removed before it enters into the natural cycle. As the 2-PrOH is water-miscible in any proportion, ion-pairing between 2-PrOH2+ and CrO3Cl- becomes very fast. As a result, Cr(VI) can easily be extracted. Therefore, the method is recommended as a simple, rapid and adaptable method to quickly separate Cr(VI) from aqueous samples.