Синтез подсистемы управления скоростью движения конвейера

We consider the problem of engine speed control conveyor. The problem is solved in the class of linear optimal regulators. As a criterion of optimality adopted quadratic functional integral characterizes the quality of the transient process and the amount of the cost of energy for movement. On the basis of the conducted research the author suggests a transitional with optimal configuration of the controller

Анализ условий и технологий эксплуатации магистральной нефтеперекачивающей станции «Раскино»

Объектом исследования является насос нефтяной магистральный. Цель работы – диагностирование общего технического состояния нефтяного магистрального насоса НМ 10000-210 нефтеперекачивающей станции "Раскино", предоставить рекомендации к техническому обслуживанию и ремонту насоса по его фактическому техническому состоянию. Основные конструктивные, технологические и технико-эксплуатационные характеристики: произведен расчет диагностирования технического состояния насосного агрегата нефтеперекачивающей станции "Раскино" на основе статистически обработанных данных, полученных с помощью измерительных приборов.The object of the study is the oil trunk pump. The purpose of the work is to diagnose the overall technical condition of the oil main pump NM 10000-210 of the oil pumping station "Raskino", to provide recommendations for maintenance and to repair of the pump according to its actual technical condition. The main design, technological and technical and operational characteristics: the calculation of the technical condition of the pumping unit of the oil pumping station "Raskino" was made on the basis of statistically processed data obtained with the help of measuring instruments

Aerobic nonylphenol degradation and nitro-nonylphenol formation by microbial cultures from sediments

Nonylphenol (NP) is an estrogenic pollutant which is widely present in the aquatic environment. Biodegradation of NP can reduce the toxicological risk. In this study, aerobic biodegradation of NP in river sediment was investigated. The sediment used for the microcosm experiments was aged polluted with NP. The biodegradation of NP in the sediment occurred within 8 days with a lag phase of 2 days at 30°C. During the biodegradation, nitro-nonylphenol metabolites were formed, which were further degraded to unknown compounds. The attached nitro-group originated from the ammonium in the medium. Five subsequent transfers were performed from original sediment and yielded a final stable population. In this NP-degrading culture, the microorganisms possibly involved in the biotransformation of NP to nitro-nonylphenol were related to ammonium-oxidizing bacteria. Besides the degradation of NP via nitro-nonylphenol, bacteria related to phenol-degrading species, which degrade phenol via ring cleavage, are abundantly present

The United States and the Balance of Power, 1812-1818

Abstract not availabl

Schicksal von 4-Nonylphenol und Bisphenol A im System Boden/Klärschlamm bei der landwirtschaftlichen Klärschlammverwertung

The fate of the important industrial chemical nonylphenol and bisphenol A which were enriched during wastewater treatment processes and exposed to the environment using sewage sludge as an agricultural fertilizier were studied. Adsorption and degradation experiments were performed with [14C]-radiolabeled compounds. Sorption of 353-nonylphenol to sandy loam soil as well as to Na-bentonite and peat humic acids was high, desorption low. Sorption and desorption of nonylphenol was strongly correlated with the amount of suspended soil in water. An enrichment of nonylphenol in soil migt be possible. In competitive sorption studies between dissolved peat humic acids and Na-bentonite about 90% of nonylphenol was sorbed to the bentonite therefore an enrichment in sediments of surface waters is expected. This is confirmed in a large number of publications. Using solid peat humic acids in competitive sorption studies most of nonylphenol (ca. 80%) was enriched at the solid peat humic acids and not at the Na-bentonite. An enrichment of nonylphenol at soil organic matter therefore is to be expected. Sorption of bisphenol A to sandy loam is low there might be a risk of contamination of ground water because of bleeding using bisphenol A contaminated sewage sludge as an agricultural fertilizier. 353-nonylphenol was stabilizied with increasing amounts of sewage sludge in soil up to 25% of applied after 135 days of incubation. A volatilization of 5% of 353-nonylphenol in a sandy loam might be an important source of nonylphenol into the environment. A new metabolite which was less polar than the parent compound nonylphenol itself was identified as 4-(3,5-dimethyl-3-heptyl)-2-nitrophenol. Highest amounts of that metabolite found in degradation studies were 40% of applied. In degradation studies after 130 days in a soil/sewage sludge mixture 1:1 (m:m) all isomers of technical nonylphenol were metabolizied in the same order to the nitro-metabolite. In sandy clay loam and in loam no nonylphenol and no metabolites of nonylphenol could be detected after 135 days of incubation in degradation experiments. In bioavailability studies degradation rates of 353-nonylphenol decreased dramatically with additional Na-bentonite or additional peat humic acids in a sandy loamy soil. 70% of applied nonylphenol could be detected after 135 days of incubation in sandy loam with additional peat humic acids. After 145 days of incubation in sewage sludge no bisphenol A and no metabolites of bisphenol A could be detected. No mutagen action could be detected for nonylphenol, 353-nonylphenol, bisphenol A and the new metabolite 4-(3,5-dimethyl-3-heptyl)-2-nitrophenol in test assays used (Ames-assay, UMU-assay). In conclusion the risk using bisphenol A contaminated sewage sludge as an agricultural fertilizier might be poor, but using nonylphenol contaminated sewage sludge there might be an incalculable risk, specially considering the high amounts of the metabolite 2-nitro-nonylphenol

Acute toxicity of 353-nonylphenol and its metabolites for zebrafish embryos

Background, aim and scope: Nonylphenol (NP) can be detected in the aquatic environment all over the world. It is applied as a technical mixture of isomers of which 353-NP is the most relevant both in terms of abundance (about 20% of total mass) and endocrine potential. 353-NP is metabolised in sewage sludge. The aims of the present study were to determine and to compare the acute toxicity of t-NP, 353-NP and its metabolites as well as to discuss if the toxicity of 353-NP changes during degradation. Materials and methods: 353-NP and two of its metabolites were synthesised. The zebrafish embryo test was performed according to standard protocols. Several lethal and non-lethal endpoints during embryonal development were reported. NOEL, LOEL and EC50 were calculated. Results: All tested compounds caused lethal as well as non-lethal malformations during embryo development. 353-NP showed a higher toxicity (EC50 for lethal endpoints 6.7 mg/L) compared to its metabolites 4-(3.5- dimethyl-3-heptyl) -2-nitrophenol (EC50 13.3 mg/L) and 4-(3,5-dimethyl-3-heptyl)-2- bromophenol (EC50 27.1 mg/L). Discussion: In surface water, concentrations of NP are far below the NOEC identified by the zebrafish embryo test. However, in soils and sewage sludge, concentrations may reach or even exceed these concentrations. Therefore, sludge-treated sites close to surface waters should be analysed for NP and its metabolites in order to detect an unduly high contamination due to runoff events. Conclusions: The results of the present study point out that the toxicity of 353-NP probably declines during metabolisation in water, sediment and soil, but does not vanish since the major metabolites exhibit a clear toxic potential for zebrafish embryos. Recommendations and perspectives: Metabolites of environmental pollutants should be included in the ecotoxicological test strategy for a proper risk assessment