Godslastering voor en na de aanslagen op Charlie Hebdo

Criminal Justice: Legitimacy, accountability, and effectivit

Математическое моделирование тепломассопереноса в канале с пористой вставкой

Выпускная квалификационная работа 105 с., 22 рис., 5 табл., 19 источников, 1 прил. Объект исследования - канал с пористым материалом, в том числе рабочая зона газогенератора. Цель работы – исследование процессов тепломассопереноса в канале, заполненном пористой вставкой, на основе математического моделирования. В работе использован пакет вычислительной гидродинамики FLUENT совместно с сеточным генератором GAMBIT. Установлены особенности использования различных приближений к математическому моделированию тепломассопереноса в каналах с пористыми вставками, а также показана возможность применения пакетов вычислительной гидродинамики для анализа термогидродинамических структур в канале газогенератора без учета влияния физико-химических особенностей процесса газификацииThe paper consists of 105 pp., 22 fig., 5 tab., 19 references, 1 appendix. The objects of study are the channel with porous material and the work area of the gasifier. The purpose of the work is heat and mass transfer processes study in the channel filled with porous insert based on mathematical modeling. CFD package FLUENT was used together with the finite element mesh generator GAMBIT. The features of the use of various approximations to the mathematical modeling of heat and mass transfer in porous inserts channels are specified. The possibility of using computational fluid dynamics package for the analysis of thermohydrodynamic structures in the channel of gasifier excluding the impact of physical and chemical characteristics of the gasification process is proved

Streptomyces inside-out: a new perspective on the bacteria that provide us with antibiotics

Many of the antibiotics used today are made by a group of bacteria called Streptomyces. Streptomycetes evolved about 450 million years ago as branched filamentous organisms adapted to the utilization of plant remains. They reproduce by sending up specialized aerial branches, which form spores. Aerial growth is parasitic on the primary colony, which is digested and reused for aerial growth. The reproductive phase is coordinated with the secretion of antibiotics, which may protect the colony against invading bacteria during aerial growth. A clue to the integration of antibiotic production and aerial growth is provided by bldA mutants, which are defective in both processes. These mutants lack the ability to translate a particularly rare codon, UUA, in the genetic code. The UUA codon (TTA in DNA) is present in several regulatory genes that control sets of antibiotic production genes, and in one, bldH that controls aerial mycelium formation. The regulatory genes for antibiotic production are all involved in self-reinforcing regulatory systems that potentially amplify the regulatory significance of small changes in the efficiency of translation of UUA codons. One of the regulatory targets of bldH is an extracellular protease inhibitor protein that is likely to delay the digestion of the primary biomass until the colony is ready for aerial growth. The use of the UUA codon to orchestrate different aspects of extracellular biology appeared very early in Streptomyces evolution