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

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

g-factor of a tightly bound electron

We study the hyperfine splitting of an electron in hydrogen-like $^{209}Bi ^{82+}$. It is found that the hfs energy splitting can be explained well by considering the g-factor reduction due to the binding effect of a bound electron. We determine for the first time the experimental value of the magnetic moment of a tightly bound electron.Comment: 6 pages, Latex, Phys. Rev. A in pres

Small Corrections to the Tunneling Phase Time Formulation

After reexamining the above barrier diffusion problem where we notice that the wave packet collision implies the existence of {\em multiple} reflected and transmitted wave packets, we analyze the way of obtaining phase times for tunneling/reflecting particles in a particular colliding configuration where the idea of multiple peak decomposition is recovered. To partially overcome the analytical incongruities which frequently rise up when the stationary phase method is adopted for computing the (tunneling) phase time expressions, we present a theoretical exercise involving a symmetrical collision between two identical wave packets and a unidimensional squared potential barrier where the scattered wave packets can be recomposed by summing the amplitudes of simultaneously reflected and transmitted wave components so that the conditions for applying the stationary phase principle are totally recovered. Lessons concerning the use of the stationary phase method are drawn.Comment: 14 pages, 3 figure

Hyperfine Anomaly of Be Isotopes and Anomalous Large Anomaly in 11^{11}Be

A new result of investigations of the hyperfine structure (hfs) anomaly in Be isotopes is presented. The hfs constant for $^{11}$Be is obtained by using the core plus neutron type wave function: $|2s_{1\over 2}>+|1d_{5\over2}\times 2^+ ; {1/2}^{+}>$. A large hfs anomaly of $^{11}$Be is found, which is mainly due to a large radius of the halo single particle state.Comment: 14 pages, Late