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the Advantages of Using Rotating Machines with Profiled Rotors

World Journal of Engineering and technology 2023年第1期11卷 41-47页

作者： Gabriel Fischer-Szava Nicolae Băran Mihaela constantin Mugurel Oprea cătălina dobre Georgiana Duiculete Beatrice Ibrean Faculty of Mechanical Engineering and Mechatronics University Politehnica of Bucharest Bucharest Romania

In order to achieve a lower consumed energy, the performance of a new type of rotating volumetric pump with two profiled rotors (variant I) which is compared with a centrifugal pump (variant II) is presented. the analysis regarding the same flow rate of transported liquid and the same pressure increases points out the conduct of the system at the variation of the key operating parameters. the actual driving power of the rotating volumetric pump is higher stating that is more advantageous in operation. the effective efficiency of the system is improved due to the original constructive solution.

关键词： Rotating Machine Volumetric Pump Profiled Rotors centrifugal Pump Energy Performances

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铅的电解精炼

引用

株冶科技 1998年第2期26卷 8-12页

作者： dobre.,t 魏文武保加利亚科学院生物化学研究所

研究了运用直流电流和周期反向电流在硅氟酸中进行铅的电解精炼的阳极和阴极过程。不用周期反向电流，在电流密度为３００Ａ／ｍ＾３（３Ａ／ｄｍ＾２）条件下，铅在高浓度认中液中电解精炼，操作６０￣８０ｈ（一个周期为９５ｈ）后阳... 详细信息

研究了运用直流电流和周期反向电流在硅氟酸中进行铅的电解精炼的阳极和阴极过程。不用周期反向电流，在电流密度为３００Ａ／ｍ＾３（３Ａ／ｄｍ＾２）条件下，铅在高浓度认中液中电解精炼，操作６０￣８０ｈ（一个周期为９５ｈ）后阳极极化电压达到极限值（ΔΦＡｃｒ＝２００ｍＡ），这时铋和锑开始自动从阳极溶解，在阴极沉积。若用周期反向电流，即使９５小时后，阳极极化电压也不会达到极限值（ΔΦＡｃｒ）。

关键词：炼铅电解精炼铋锑

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Physico-chemical and Microbiological Assessment of Organic Pollution in Plain Salty Lakes from Protected Regions

引用

Journal of Environmental Protection 2017年第12期8卷 1474-1489页

作者： Veronica Lazar carmen curutiu Ditu Lia-Mara Alina Holban Irina Gheorghe Florica Marinescu Mihaela Ilie Alex Ivanov Dumitru dobre Mariana carmen chifiriuc Botany-Microbiology Department Faculty of Biology University of Bucharest Bucharest Romania the Research Institute of the University of Bucharest Bucharest Romania Maximilian Association Buzau Romania the National Institute for Research and Development in Environmental Protection-INcDPM Bucharest Romania

One of the most important goals of EU nature and water framework directives is to ensure healthy aquatic ecosystems by the protection of the most valuable species and habitats form the Natura 2000 network, while at the same time ensuring a balance between water/nature protection and the sustainable use of nature’s natural resources. the purpose of this study was to evaluate the physico-chemical and microbiological characteristics of four Romanian salty plain lakes included in Natura 2000 Network, in order to assess the degree of organic pollution and to generate the knowledge required for the design and implementation of appropriate measures for maintaining the balance between the water protection and the sustainable use of these protected ecosystems. the water and sediment sampling was performed in two consecutive years (2015 and 2016), in September and the following standard parameters have been determined: pH, chemical oxygen consumption (cOc), the degree of trophicity and salinity of the environment, metals content, microbiological indicators and microbial physiological groups involved in nutrient cycling. the pH ranged from 7.56 to 8.93, close or above the upper normal limit of 8.5, being correlated with a high salinity characteristic of chlorinated, sulphated, high sodium and magnesium content waters. Despite the similar values recorded for the physico-chemical parameters in the two consecutive years suggesting a certain degree of stability of the investigated aquatic ecosystems, the cOc values indicate a high degree of hypertrophy, which could be attributed to the reduced surface area, ecological pisciculture and agriculture input. the microbiological parameters revealed the existence of both recent and chronic fecal pollution source. the high hypertrophy degree could represent a positive premise for the high productivity of the investigated ecosystems, but also an alarm signal for excessive organic pollution, with the risk of redox potential decrease which c

关键词： Salty Lakes Physico-chemical characteristics Microbiological Parameters Protected Ecosystems Hypertrophy

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the Long term Evolution of Phosphates from the cambic chernozem at ARDS caracal, Romania

引用

Journal of Life Sciences 2012年第5期6卷 557-562页

作者： Ana Maria Dodocioiu Romulus Mocanu Marian dobre University of craiova Craiova 200585 Romania

the decreasing of the plant available phosphorus of Romanian soils after 1990 is a major concern in relation with the lowered yields of the major crops. this fact is correlated with a rudimentary technology where the fertilization is a secondary issue. thus, the fertilizer consumption, after 1990, has drastically decreased to 41.3 kg/ha NPK on arable land over 129.9 kg/ha in 1986 and from 86.4 kg/ha to 26.3 kg/ha on agricultural land. As a result, the phosphorus fertilizer quantities applied by small farmers are very small or inexistent. In order to determine the soil available phosphorus content in Romania, it was analyzed the evolution of soil phosphorus supplying degree on a cambic chernozem (one of the most fertile soils in Romania) from Agricultural Research and Development Station (ARDS) caracal between 1986-1992 and 2000-2005. this analysis has shown the following issues: very well supplied soils by available phosphorus no more exist since 2006, the ones with a good supplying degree have decreased from 616 ha to 107 ha, which means from 24.8% to 4.3% yet the low supplied soils have increased from 526 ha to 1,129 ha (23.1% to 45.5%) and the very low supplied ones have increased from 198 ha to 776 ha (7.9% to 31.2%). As a consequence of low fertilizer quantities and the decreasing of the soil supplying degree by available phosphorus the average yield in this farm has decreased from 5,776 to 3,707 kg/ha.

关键词：罗马尼亚磷酸盐土壤速效磷含量演进黑土农作物产量氮磷钾肥农业用地

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