Abstract: Ni4Ti3 precipitates play an important role in the shape memory and superelastic behaviour of thermo-mechanically treated Ni-Ti material. The 3D morphology and distribution of such precipitates with lenticular shape and rhombohedral atomic structure in the austenitic B2 matrix of a binary Ni-rich Ni-Ti alloy has been elucidated via a slice view procedure in a Dual-Beam FIB/SEM system. With the sequence of cross-section SE images obtained from the SEM, a 3D reconstruction has been achieved after proper alignment and image processing, from which both qualitative and quantitative analysis can be performed. Careful imaging is needed to ensure that all variants of the precipitates are observed with equal probability, regardless sample orientation. Moreover, due to the weak contrast of the precipitates, proper imaging conditions need to be selected to allow for semi-automated image treatment. Finally, a volume ratio of 10.2% for the Ni4Ti3 precipitates could be calculated, summed over all variants, which yields a net composition of Ni50.36Ti49.64 for the matrix, leading to an increase of 113 degrees for the martensitic start temperature Ms. Also, the expected relative orientation of the different variants of the precipitates could be confirmed. In the near future, other quantitative measures on the distribution of the precipitates can be expected.

Abstract: In this paper, we consider the bulky knots and bulky links, which appear after cutting of a Generalized MöbiusListing GMLn2 body (with the radial cross section a convex plane 2-symmetric figure with two vertices) along a different Generalized MöbiusListing surfaces GMLn2 situated in it. The aim of this report is to investigate the number and geometric structure of the independent objects that appear after such a cutting process of GMLn2 bodies. In most cases we are able to count the indices of the resulting mathematical objects according to the known classification for the standard knots and links.

Abstract: The development cost-effective life support technologies is a highly relevant topic for space biology. Currently, food and water supply during space flights is currently restricted by technical and economic constraints: daily water consumption of an average crew of 6 members is about 72 L, with an estimated cost of 2,160,000 d-1. To reduce these costs and sustain long term space missions, the European Space Agency designed MELiSSA, an artificial ecosystem based on 5 compartments for the recycling gas, liquid and solid waste (Lasseur et al., 2011). In the CI stage, crew and inedible solid waste is fermented by thermophilic anaerobic bacteria, producing volatile fatty acids (VFAs), CO2 and ammonium (NH4+). In the CII compartment the VFAs are converted into edible biomass, using the photoheterotroph Rodospirillum rubrum. Afterwards, the nitrifying CIII unit converts toxic levels of ammonia/ammonium into nitrate, which enables the effluent to be fed to the photoautotrohopic CIV stage, that provides food and oxygen for the crew (Godia et al., 2002). The highest nitrogen flux in a Life Support System is human urine. As nitrate is the preferred form of nitrogen fertilizer for hydroponic plant cultivation, urine nitrification is an essential process in the MELiSSA loop. The development of the Additional Unit for Water Treatment or Urine NItrification ConsortiUM (UNICUM) requires the selection and characterization of the microorganisms that will be used. The key microorganisms in the biological treatment of urine are heterotrophs, for the hydrolysis of urea into ammonia and carbon dioxide, Ammonia Oxidizing Bacteria (AOB), for the ammonia oxidation into nitrite and Nitrite Oxidizing Bacteria (NOB), for the conversion of nitrite into nitrate. The strains were selected according to predefined safety (non sporogenic and BSL 1) and metabolic (Ks, μmax) criteria. To evaluate functional consortia for space applications, ureolysis, nitritation and nitratation of the selected microorganisms and synthetic communities were elucidated. Additionally, urine is a matrix with a high salt content. Unhydrolised urine's EC ranges from 1.1 to 33.9 mS/cm, the mean value being 21.5 mS/cm (Marickar, 2010), while hydrolysed urine can reach higher levels, up to 75 mS/cm. This conditions could inhibit microbial metabolism, therefore the effect of salinity on urine nitrification was also elucidated.

Abstract: Airborne dust particles were collected in a return airway of a South African gold mine using a 7-stage, single-orifice cascade impactor. Between 70 and 130 individual particles were analysed on each stage using automated electron-probe x-ray microanalysis (EPXMA). Particle size and shape parameters are given for different classes of particles sorted by elemental composition. Silicon-rich particles are the most abundant overall, while chlorine-rich particles dominate (up to 80%) in the range 0.21.0 μm. It is shown that EPXMA characterisation of particles can be used to infer relative contributions of various particle sources and dust generating processes to the total dust concentrations in mine atmospheres. An understanding of the nature and source of particles is essential for any source control strategy. We conclude that the EPXMA technique merits inclusion in the repertoire of techniques used for characterising underground dust.

Abstract: Ammonia-oxidizing microorganisms (AOB and AOA) and nitrite oxidizing bacteria (NOB) are the most important organisms responsible for ammonia and nitrite oxidation in agricultural ecosystems and growing media. Ammonia and nitrite oxidation are critical steps in the soil nitrogen cycle and can be affected by the application of mineral fertilizers or organic fertilizers. The functionality of the microbial community has a major impact on the nutrient turnover and will finally influence plant performance. The microbial community associated with the growing medium and its functionality will also be influenced by the rhizosphere and the bulk soil. In our study, we used a tomato plant with a high root exudation capacity in order to stimulate microbial activity. We studied plant performance in rhizotrons (a phentotyping system for imaging roots), including an optical method (planar optodes) for non-invasive, quantitative and high-resolution imaging of pH dynamics in the rhizosphere and adjacent medium. The horticultural growing medium was supplemented with organic-derived nitrogen or ammonium derived from struvite. The possible differences in the root structure between treatments is compared with the total root length. Destructive growing medium sampling and high throughput sequencing analysis of the bacterial abundance of the communities present in the rhizosphere and the bulk soil is used to study the growing medium-associated microbial community structure and functionality, and this will be related to pH changes in the rhizosphere and the bulk soil. Our hypothesis is that the growing medium-associated microbial community structure changes depending on the nitrogen form provided and we expect a higher abundance of bacteria in the treatment with organic fertilizer and a higher abundance of AOB and NOB in the rhizosphere in comparison to the bulk soil.