Анализ влияния конструктивных особенностей башенных и вентиляторных градирен на их тепловую эффективность и показатели энергоблоков

Выпускная квалификационная работа 159 страниц, 37 рисунков, 4 таблицы, 103 источника, 5 приложений. Объектами исследования являются различные конструкции градирен энергетических и промышленных предприятий. Цель работы – на основе параметрического анализа различных градирен, выполненного по усовершенствованным методикам, выявить влияния конструктивных особенностей различных градирен на их эффективность и показатели энергоблоков. Для достижения поставленной цели необходимо решить следующие задачи: Совершенствование и автоматизация методик расчета теплотехнических характеристик башенных градирен. Совершенствование и автоматизация методик расчета теплотехнических характеристик вентиляторных градирен. Совершенствование и автоматизация методики расчета теплотехнических характеристик вихревой камеры. Проведение параметрического анализа по полученным результатам расчетов. В процессе выполнения темы создано усовершенствованное методическое обеспечение для расчетов эффективности охлаждения градирен различных типов, позволяющее сократить сроки и снизить затраты на разработку эффективных вариантов, которое может использоваться инженерами по эксплуатации энергетического оборудования для его диагностирования. Тестирование составленных программ осуществлено сравнением результатов с известными решениями, полученными ранее.Final qualifying work contains 159 pages, 37 figures, 4 tables, 103 sources, 5 annexed. The object of the study are different designs of the cooling tower of power and industrial facilities. The purpose of work - based on parametric analysis of different cooling towers, made by advanced technology, to determine the effect of the design features of various towers on their efficiency and equipment productivity. To achieve this goal it is necessary to solve the following tasks: To improve and automate the method for calculating the thermal performance of cooling towers. To improve and automate the method for calculating the thermal performance of the cooling fan. To improve and automate the method of method of calculating the thermal characteristics of the vortex chamber. Conduct par

Lorentz Invariant Superluminal Tunneling

It is shown that superluminal optical signalling is possible without violating Lorentz invariance and causality via tunneling through photonic band gaps in inhomogeneous dielectrics of a special kind.Comment: 10 pages revtex, no figure, more discussions added, submitted to Phys. Rev.

Ecotoxicological characterization of biochars : role of feedstock and pyrolysis temperature

Seven contrasting feedstocks were subjected to slow pyrolysis at low (300 or 350 °C) and high temperature (550 or 600 °C), and both biochars and the corresponding feedstocks tested for short-term ecotoxicity using basal soil respiration and collembolan reproduction tests. After a 28-d incubation, soil basal respiration was not inhibited but stimulated by additions of feedstocks and biochars. However, variation in soil respiration was dependent on both feedstock and pyrolysis temperature. In the last case, respiration decreased with pyrolysis temperature (r = − 0.78; p < 0.0001, n = 21) and increased with a higher volatile matter content (r = 0.51; p < 0.017), these two variables being correlated (r = − 0.86, p < 0.0001). Collembolan reproduction was generally unaffected by any of the additions, but when inhibited, it was mostly influenced by feedstock, and generally without any influence of charring itself and pyrolysis temperature. Strong inhibition was only observed in uncharred food waste and resulting biochars. Inhibition effects were probably linked to high soluble Na and NH4 concentrations when both feedstocks and biochars were considered, but mostly to soluble Na when only biochars were taken into account. The general lack of toxicity of the set of slow pyrolysis biochars in this study at typical field application rates (≤ 20 Mg ha− 1) suggests a low short-term toxicity risk. At higher application rates (20-540 Mg ha− 1), some biochars affected collembolan reproduction to some extent, but only strongly in the food waste biochars. Such negative impacts were not anticipated by the criteria set in currently available biochar quality standards, pointing out the need to consider ecotoxicological criteria either explicitly or implicitly in biochar characterization schemes or in management recommendations

Political opportunism and countercyclical fiscal policy in election-year recessions

Political budget cycles (PBCs) have been well documented in the literature, albeit not for all circumstances. Similarly, there is clear evidence on the positive effect of economic growth on electoral success. However, no work has been done on the impact of economic growth on the magnitude of PBCs. The theoretical model argues that a government has an incentive to increase fiscal manipulations when a recession is expected to hit and curtail reelection chances; this amounts to countercyclical policy for opportunistic rather than Keynesian motives. Very robust evidence for this behavior is found in Portuguese municipalities; in election years, budget deficits go up even more and significantly so, when a recession is expected.Fundação para a Ciência e Tecnologia (FCT

How Do Tourists React to Political Violence? An Empirical Analysis of Tourism in Egypt

This paper uses a detailed database of political violence in Egypt to study European and US tourists' attitudes towards a conflict region. We study the heterogeneous impacts of different dimensions of political violence and counter-violence on tourist flows to Egypt in the 1990s. Both US and EU tourists respond negatively to attacks on tourists, but are not influenced by casualties arising in confrontations between domestic groups. However, European tourists are sensitive to the counter-violence measures implemented by the Egyptian government. There is also evidence of arrivals of tourists into Egypt rising when fatalities in the Israeli/Palestinian conflict increase.</p

Hyperfine Structure Constants for Eu Isotopes: Is The Empirical Formula of HFS Anomaly Universal ?

We calculate the hyperfine structure constant for the Eu isotopes with shell model wave functions. The calculated results are compared with those predicted by the Moskowitz-Lombardi (M-L) empirical formula. It turns out that the two approaches give the very different behaviors of the hfs constants in the isotope dependence. This should be easily measured by experiment, which may lead to the universality check of the M-L formula.Comment: 18 pages, Latex, two figure