Experience in using a guide vane design with a “floating” lower bearing

Conclusion The use of the floating bearing of the vanes in the lower ring of the gate apparatus makes it possible to reduce the cycle and labor expenditures of manufacture at the plant and on assembly of the gate apparatus with a substantial improvement of the quality of assembly.Translated from Gidrotekhnicheskoe Stroitel'stvo, No. 4, pp. 45–47, April, 1984.     

Integrated Water Resources Management in the Republic of Uzbekistan

Abstract

The Uzbek socio-economic structure is characterized by the transition from a centrally-planned to a market-orientated economy, with a shifting from agricultural production to industrial development. However, the agricultural sector continues to play a significant role in a general economy of the country. The major water sector strategy is to decrease the dependence of agricultural production on climate by introducing advanced irrigation techniques and water saving methods to achieve future sustainable socio-economic development and environmental protection. Water management policy should be flexible enough to adapt to new demands. The regulation of consumption through demand management tools, such as appropriate pricing policies, has recently received greater attention in Uzbekistan. The main thesis of this paper is that allocation of water resources cannot be separated from ecological and economic considerations. The establishment of development objectives and the identification of constraints are also discussed. In the coming years, special attention will need to be paid to the control of water pollution and land salinization, water resources conservation, and acknowledging that actions to increase water productivity are as important as finding additional sources of water.     

乌江沙沱水电站水轮机选型分析

沙沱水电站水头运行范围50～74.9 m.电站受阻出力多为汛期季节性电能,在综合考虑减少受阻出力及水轮机稳定运行的情况下,对61、62.5、64、65.5、67m五个额定水头方案进行了比较分析,最终确定了经济、合理的水轮机参数.     

A knowledge management methodology for the integrated assessment of WWTP configurations during conceptual design

The current complexity involved in wastewater management projects is arising as the XXI century sets new challenges leading towards a more integrated plant design. In this context, the growing number of innovative technologies, stricter legislation and the development of new methodological approaches make it difficult to design appropriate flow schemes for new wastewater projects. Thus, new tools are needed for the wastewater treatment plant (WWTP) conceptual design using integrated assessment methods in order to include different types of objectives at the same time i.e. environmental, economical, technical, and legal. Previous experiences used the decision support system (DSS) methodology to handle the specific issues related to wastewater management, for example, the design of treatment facilities for small communities. However, tools developed for addressing the whole treatment process independently of the plant size, capable of integrating knowledge from many different areas, including both conventional and innovative technologies are not available. Therefore, the aim of this paper is to present and describe an innovative knowledge-based methodology that handles the conceptual design of WWTP process flow-diagrams (PFDs), satisfying a vast number of different criteria. This global approach is based on a hierarchy of decisions that uses the information contained in knowledge bases (KBs) with the aim of automating the generation of suitable WWTP configurations for a specific scenario. Expert interviews, legislation, specialized literature and engineering experience have been integrated within the different KBs, which indeed constitute one of the main highlights of this work. Therefore, the methodology is presented as a valuable tool which provides customized PFD for each specific case, taking into account process unit interactions and the user specified requirements and objectives.     

Automated image analysis of Euglena gracilis Klebs (Euglenophyta) for measuring sublethal effects of three model contaminants

The short-term impacts of atrazine (herbicide), tributyltin (organometal) and copper on the behaviour of Euglena gracilis Klebs (Euglenophyta) were assessed. First, the ECOTOX automated image analysis system was used, which measured swimming velocity, cell shape, percentage of cells swimming upwards, and randomness of swimming. Next, visual observation by microscopy was used to measure percentage of cell motility and cell shape. Behavioural changes can be used as an indicator of stress in less than 24 h, potentially making them suitable for inclusion in early-warning systems for water quality. Findings indicate that E. gracilis is a very sensitive organism to copper, showing inhibition of motility with visual observation at 0.8 μmol/L within 1 h. The image analysis system was in general less sensitive than visual observation for detecting behavioural changes after incubation in copper. In contrast, after exposure to organic contaminants atrazine and tributyltin, the ECOTOX system detected small changes in the number of cells swimming upwards (antigravitactic behaviour) at higher concentrations.     

Effect of the outlet angle β2 on the characteristics of low specific-speed centrifugal pumps

Conclusions An experimental check of various low specific-speed pumps showed that on changing the geometry of the vaning of the impeller, in conformity with the recommendations [1], the main feature of which is an increase of the outlet angles of the vanes to values 90°₂130° and installation of short intermediate vanes in the passages between the main vanes, the head increases considerably without a decrease of pump efficiency.For centrifugal pumps with a volute and diffuser whose impellers have a different number of main vanes, the most rational is the installation of three intermediate vanes in each vane passage with a change in the direction of the flow by the main vane toward an increase of the outlet angle on diameter D₂=0.5–0.65D₃ for fecal pumps and pumps with short vanes.The use of the new impeller design is especially effective for high rotative-speed pumps. For multistage submersible pumps with a guide-vane apparatus at the inlet and axial outlet, the optimal variant is the installation of one intermediate vane with a start of the change in the flow direction D₃=0.63D₂.In conclusion, it is necessary to note that all tests were conducted without modifying the casing and branch pipes, which leaves room for a further increase of the head developed by pumps with the new type of impeller.Translated from Gidrotekhnicheskoe Stroitel'stvo, No. 5, pp. 21–25, May, 1982.     

Modern conveyor transportation and prospects for its use in hydraulic construction

An analysis of the experience in the Soviet Union and in foreign countries with conveyor transportation in the mining industry, as well as with use of conveyors in hydraulic construction shows that the introduction of conveyor transportation in the field of construction of embankment dams in this country, for delivery of earth-rock material from quarries, as well as for carrying raw materials to concentrating plants processing nonmetallic minerals, will make it possible.