Modeling and analysis of own oscillations of the TFB with turbine 500 Mw

Проведен анализ собственных колебаний системы турбоагрегат-фундамент-основание с турбиной мощностью 500 МВт в частотном диапазоне приближенном к частоте колебаний электромагнитной природы от генератора. Объектом исследования является система турбоагрегат-фундамент-основание.. Для исследования выбрана система с паровой турбиной, которая содержит несколько типовых корпусов. Для моделирования и проведения численных расчетных исследований использован метод конечных элементов. Построены геометрические и конечно-элементные модели системы турбоагрегат-фундамент-основание с учетом особенностей взаимодействия гибких корпусов турбины с фундаментом. Проведены расчеты собственных колебаний. Получены собственные частоты и формы колебаний. Полученные результаты дают качественную оценку причин повышенной вибрации отдельных элементов рассматриваемой системы.The analysis of the own oscillations of the turbounit-foundation-base system is carried out. The system includes a reinforced concrete foundation, a 500 MW turbine with five bodies, a generator and four condensers. To study the chosensystem with a steam turbine, which contains several typical buildings. The relevance of the study is due to the presence of turbounit-foundation-base systems with a long operating time and a significant development of the base resource of increased levels of vibration. On the other hand, the relevance and novelty of the results is due to the lack of previousresearch on the given object and subject of research. A system with a steam turbine with four typical identical flexible housings and one rigid body of high weight is considered. The system of turbine-base-base in the frequency range close to the frequency of oscillations of electromagnetic naturefrom the generator was considered. The object of the study is a turbo-base-base system. The method of finite elements is used for modeling and conducting numerical calculations. The geometric and finite-element models of the turbo unit-foundation-base system are constructed taking into account the features of the interaction of flexible bodies of the turbine with the foundation. The modeling of the foundation is done using a system of core and mass finite element. The rigid body of the steam turbine and the generator were modeled using a system of massive finite elements. The most flexible bodies of the steam turbine weremodeled using a shell, coreand mass finite element system. The basis was modeled using the system of stiffness and boundary conditions. Capacitors were modeled using a system of stiffness and boundary conditions. The peculiarity of the calculation models is the detailed three-dimensional modeling of flexible bodies of the steam turbine. The applied simulation technique is unique and allows us to carry out a detailed analysis of the system's own oscillations. The calculations of proper oscillations have been carried out. Own frequencies and forms of oscillations are obtained.The obtained results give a qualitative estimation of the internal oscillations of separate elements of the considered system of the turbo-aggregate-foundation-base and the system as a whole. The results ofthe calculations were used inthe study of the causes of increased vibration of the turbo unit-foundation-base system and its individual elements

О механизме сольватации ионов и радиусах сольватированных ионов галогеноводородов в н-спиртах

На основе предложенной модификации двухслойной модели Абрахама и Лиси рассчитаны эффективные радиусы (rᵢ) и величины изменения энергии Гиббса сольватации (ΔcGᵢ⁰) для бромид-, иодид-ионов и ионов Н⁺ в ряду н-спиртов от метанола до октанола при 5-55°С. Показано, что данная модификация согласуется с механизмом сольватации ионов, который сводится к уменьшению свободной энергии системы за счет нейтрализации заряда иона и перераспределения заряда с окружающими молекулами растворителя.Modification of double-layer model Abraham-Liszi is offered by authors both effective radii (rᵢ) and values of changes of Gibbs energy solvation (ΔcGᵢ⁰) for bromide- and iodide-ions in a series of primary alcohols from methanol to octanol are calculated at 278.15-328.15 K on the basis of this modification. The latter consider the mechanism of ions solvation better. This mechanism takes into account reduction of a free energy of system at the expense of neutralization of an ion charge and redistribution of a charge with environmental solvent molecules

Разработка модуля защищённого документооборота с использованием гибридной криптосистемы

This article describes the process of creation hybrid cryptosystem. Also considered the creation of extensions for the browser

High level of treatment failure with commonly used anthelmintics on Irish sheep farms

peer-reviewedBackground: In 2013 a Technology Adoption Program for sheep farmers was established to encourage the implementation of best management practices on sheep farms in Ireland. There were 4,500 participants in this programme in 2013. As part of this programme, farmers had the option to carry out a drench test to establish the efficacy of their anthelmintic treatment. Results: Flock faecal samples were collected before and after treatment administration and gastrointestinal nematode eggs enumerated. In total there were 1,893 participants in the task, however only 1,585 included both a pre- and post-treatment faecal sample. Of those, 1,308 provided information on the anthelmintic product that they used with 46%, 23% and 28% using a benzimidazole (BZ), levamisole (LEV) and macrocyclic lactone (ML) product respectively. The remaining farmers used a product inapplicable for inclusion in the task such as a flukicide or BZ/LEV combination product. Samples were included for analysis of drench efficacy if the pre-treatment flock egg count was ≥200 eggs per gram and the interval post-sampling was 10–14 days for BZ products, 4–7 days for LEV products and 14–18 days for ML products. These criteria reduced the number of valid tests to 369, 19.5% of all tests conducted. If the reduction post-treatment was ≥95% the treatment was considered effective. Only 51% of treatments were considered effective using this criterion. There was a significant difference in efficacy between the anthelmintic drug classes with BZ effective in only 30% of treatments, LEV effective in 52% of cases and ML effective in 76% of cases. Conclusions: Gastrointestinal nematode anthelmintic treatments, as practiced on Irish farms, have a high failure rate. There was a significant difference between the efficacies of the anthelmintic classes with BZ the least effective and ML the most effective

NcGRA2 as a molecular target to assess the parasiticidal activity of toltrazuril against Neospora caninum

The treatment of Neospora caninum infection in the bovine host is still at an experimental stage. In contrast to the in vivo situation, a wide range of compounds have been intensively investigated in cell-culture-based assays. Tools to demonstrate efficacy of treatment have remained conventional including morphological and cell biological criteria. In this work, we present a molecular assay that allows the distinction between live and dead parasites. Live parasites can be detected by measuring the mRNA level of specific genes, making use of the specific mRNA available in live cells. The NcGra2 gene of N. caninum, which is known to be expressed in both tachyzoites and bradyzoites, was used to establish a quantitative real-time RT-PCR, for monitoring parasite viability. Validation of the system in vitro was achieved using Neospora-infected cells that had been treated for 2-20 days with 30μg/ml toltrazuril. NcGRA2-RT-real time PCR demonstrated that a 10-day toltrazuril-treatment exerted parasitostatic activity, as assessed by the presence of NcGRA2-transcripts, whereas after a 14-day treatment period no NcGRA2-transcripts were detected, showing that the parasites were no longer viable. Concurrently, extended culture for a period of 4 weeks in the absence of the drug following the 14-day toltrazuril treatment did not lead to further parasite proliferation, confirming the parasiticidal effect of the treatment. This assay has the potential to be widely used in the development of novel drugs against N. caninum, with a view to distinguishing between parasiticidal and parasitostatic efficacy of given compound