Visualization of Merging Flow by Usage of PIV and CFD with Application to Grate-Kiln Induration Machines

One way to upgrade iron ore is to process it into pellets. Such a process includes several stages involving complex fluid dynamics. In this work, focus is on the grate-kiln pelletizing process and especially on the rotary kiln, with the objective to get a deeper understanding of the aerodynamics in order to improve the combustion. A down-scaled, simplified model of the real kiln is created and both numerical and experimental analyses of the flow field are performed. Conclusions are that steady state simulations can be used to get an overview over the main features of the flow field. Precautions should though be taken when analyzing the recirculation zone since steady state simulations do not capture the transient, oscillating behavior of the flow seen in the physical experiment. These oscillations will under certain conditions considerably affect the size of the recirculation zone

The Extent and Role of Domestic Tourism in a Small Island: The Case of the Isle of Man

This article presents a case concerning microdomestic tourism on the Isle of Man, British Isles. Despite being a small island, research highlights that considerable domestic tourism occurs (referred to as microdomestic tourism to reflect the small island size and distinguish from wider British Isles tourism), including day trips and overnight stays. Participants identified such behavior as touristic, and distinct from other leisure activities. Qualitative interviews with residents explore the nature of and reasons for microdomestic tourism within a small island. Breaks from routine, entertaining friends and family, and exploring less well known landscapes are shown to underpin. Highlighted is that microdomestic tourism has a variety of potential benefits, which may counter some of the restrictions typically faced by a small island community. Support for an otherwise ailing tourism industry may help to protect facilities and infrastructure used by the wider community, maintain tourism capacity, and provide atmosphere attractive to foreign visitors

PLoS Genet

The influence of mono-ubiquitylation of histone H2B (H2Bub) on transcription via nucleosome reassembly has been widely documented. Recently, it has also been shown that H2Bub promotes recovery from replication stress; however, the underling molecular mechanism remains unclear. Here, we show that H2B ubiquitylation coordinates activation of the intra-S replication checkpoint and chromatin re-assembly, in order to limit fork progression and DNA damage in the presence of replication stress. In particular, we show that the absence of H2Bub affects replication dynamics (enhanced fork progression and reduced origin firing), leading to gammaH2A accumulation and increased hydroxyurea sensitivity. Further genetic analysis indicates a role for H2Bub in transducing Rad53 phosphorylation. Concomitantly, we found that a change in replication dynamics is not due to a change in dNTP level, but is mediated by reduced Rad53 activation and destabilization of the RecQ helicase Sgs1 at the fork. Furthermore, we demonstrate that H2Bub facilitates the dissociation of the histone chaperone Asf1 from Rad53, and nucleosome reassembly behind the fork is compromised in cells lacking H2Bub. Taken together, these results indicate that the regulation of H2B ubiquitylation is a key event in the maintenance of genome stability, through coordination of intra-S checkpoint activation, chromatin assembly and replication fork progression

Combustion and Emission Challenges at LKAB

Proceedings from SESSION 1: MULTIFUEL COMBUSTIONIncreased production combined with stringent emission regulations and growing energy prices has initiated a number of activities at LKAB to investigate and evaluate alternatives to the company’s current combustion technology and fuels. Reduction of NOx emissions is, for example, one of these activities. The NOx work at LKAB has been going on for the last decade and has included both primary and secondary control measures. Work with primary measures has comprised pre-studies, physical and numerical modelling work, pilot scale and full scale trials in both Straight-Grate and Grate-Kiln pelletizing plants. Secondary measures have consisted of both SCR and SNCR studies. LKAB is also the first and only mining company in the world that have installed an SCR system in an existing Grate-Kiln plant. LKAB’s experimental combustion furnace, that is operated with high excess air ratios (n ≈ 5-6) and high combustion air temperatures (900 – 1300°C), has played a major role in these NOx investigations. It has, for example, been used to evaluate options to reduce NOx-emissions from Straight-Grate pelletizing plants during 2009. Specifically, different combustion configurations were tested including a pre-combustor, secondary air, wateroil mixtures and gas fuel. Except for the use of gas fuels, all these configurations showed a significant NOx-reduction compared to the current reference case. With the precombustor and a secondary air temperature of 450 °C the NOx-emissions could be reduced by approximately 65 %. The NOx emissions can be reduced even further with lower secondary air temperature but with the consequence of higher energy cost.Christian Fredriksson, Daniel Marjavaara, Fia Lindroos, Samuel Jonsson, Stefan Savonen, Neil Smit

Hydroxyurea-Mediated Cytotoxicity Without Inhibition of Ribonucleotide Reductase

SummaryIn many organisms, hydroxyurea (HU) inhibits class I ribonucleotide reductase, leading to lowered cellular pools of deoxyribonucleoside triphosphates. The reduced levels for DNA precursors is believed to cause replication fork stalling. Upon treatment of the hyperthermophilic archaeon Sulfolobus solfataricus with HU, we observe dose-dependent cell cycle arrest, accumulation of DNA double-strand breaks, stalled replication forks, and elevated levels of recombination structures. However, Sulfolobus has a HU-insensitive class II ribonucleotide reductase, and we reveal that HU treatment does not significantly impact cellular DNA precursor pools. Profiling of protein and transcript levels reveals modulation of a specific subset of replication initiation and cell division genes. Notably, the selective loss of the regulatory subunit of the primase correlates with cessation of replication initiation and stalling of replication forks. Furthermore, we find evidence for a detoxification response induced by HU treatment