Slicing of silicon into sheet material. Silicon sheet growth development for the large area silicon sheet task of the low cost silicon solar array project

Fabrication of a prototype large capacity multiple blade slurry saw is considered. Design of the bladehead which will tension up to 1000 blades, and cut a 45 cm long silicon ingot as large as 12 cm in diameter is given. The large blade tensioning force of 270,000 kg is applied through two bolts acting on a pair of scissor toggles, significantly reducing operator set-up time. Tests with an upside-down cutting technique resulted in 100% wafering yields and the highest wafer accuracy yet experienced with MS slicing. Variations in oil and abrasives resulted only in degraded slicing results. A technique of continuous abrasive slurry separation to remove silicon debris is described

Balanced-bellows spirometer

Compact balanced-bellows dry type spirometer was designed to be insensitive to acceleration fields along any or all coordinate axes. It provides true indication of respiratory action of test subject without need for calibration in acceleration fields

Effect of Ergot-Contaminated Barley on GrowingFinishing Pig Performance

Barley samples from Allamakee County were used in a swine feeding study. Pigs fed a barley-corn and soybean meal (SBM) diets containing up to 0.18% ergot (1.62 ppm ergot alkaloids) performed similarly to pigs fed a basal corn-SBM diet. In general, the level of ergot contamination in the final diets was insufficient to depress the performance of growing and finishing pigs

Surface structure on abandoned upland blanket peatland tracks

Temporary permissions are often granted for track use on peatlands. However, even when peatland track designs attempt to minimise environmental impacts via use of mesh systems, such linear disturbances may have persistent impacts. We evaluated the surface peatland structure of five abandoned tracks (four with a mesh surface, one unsurfaced) with varying past usage frequencies, at an upland site in northern England. Simplification of the surface nanotopography was found on all tracks compared to surrounding control areas, with increased micro-erosion patterns in rutted areas, and invasive species on some treatments. The frequency of previous usage was not found to be a significant factor controlling nano-topographic loss. Edge effects and hillslope position were influential in places, but these effects were not consistent across treatments. Nano-topographic recovery was found to be inhibited when track usage commenced within a short time frame after track construction. Mesh tracks appear to create a spatial constraint leading to poor development of plants and a reduced ability to form characteristic structures which are integral to mire function

Blanket bogs exhibit significant alterations to physical properties as a result of temporary track removal or abandonment

Temporarily consented tracks made from high-density polyethylene (HDPE) mesh have been used to mitigate both the physical and ecological impacts on peatlands from low-frequency vehicle usage. However, the impacts of mesh track removal or abandonment at the end of the consented period remain poorly understood. Over a 2-year period, we studied replicate sections of abandoned mesh track which, at the start of the experiment, had been unused for approximately 5 years, on a UK blanket bog. Some sections were removed (using two treatment methods – vegetation mown and unprepared), whereas others were left in situ. Metrics were compared both between treatments and to undisturbed reference areas. Significant differences in surface soil moisture were found between abandoned and removed tracks depending on season. Control areas had higher volumetric soil moisture than track locations. Compaction was significantly higher across all track locations in comparison to controls (p < 0.001), but rarefaction was not recorded post-removal, suggesting long-term deformation. Overland flow events were recorded in rut sections for a mean of 16% of the time, compared to <1% in control areas. Sediment traps on the tracks collected 0.406 kg compared to 0.0048 kg from the control traps, equating to a per trap value of 7.3 g from track samplers and 0.17 g from control samplers. Erosion and desiccation features occurred on both removed and abandoned track sections. Both abandonment and removal of mesh tracks have a wide range of impacts on the physical properties of peatlands, suggesting that only where access is a necessity should such a track be installed

Orbit Assembly Of Unmanned Spacecraft

In future, the mission demands on unmanned spacecraft, (whether they be Earth orbiters or deep space probes) , will be so great and so complex as to preclude their being small enough to be launched from Earth by chemical rocket. Such spacecraft can be assembled in Earth orbit by suited astronauts, using pre-fabricated modules specifically designed for such orbital assembly. These modules could be standardized, so that any number of spacecraft and mission requirements could be accommodated without extensive need for specialized hardware

Towards a better understanding aquatic carbon losses from lowland peatlands across England and Wales

Hydrological fluxes in lowland peatlands can be challenging to measure but they drive poorly understood aquatic carbon fluxes which may form an important part of the overall carbon budget for peatlands. In this study we examined 11 lowland peatland sites across some of the most important fen and raised bog complexes in England and Wales including agricultural peatlands, mining sites and restoration sites. These were intensively monitored between January 2013 and December 2015. The monitoring included continual hydrological measurements and regular sampling for dissolved organic and inorganic carbon (DOC and DIC), particulate organic carbon (POC) and dissolved carbon dioxide, methane and nitrous oxide. These data were used to calculate the amount of water flowing out of each site and the total aquatic carbon loss. In addition, the hydrological data were used to provide contextual data to explain carbon flux variations between sites and help explain and model variations in gaseous carbon fluxes. The hydrology of all these lowland peat sites is typically complex with most having been drained, which when combined with their relatively flat gradients results in most having no clear single outlet. In addition the drainage networks are often used to not only drain water during periods of excess rainfall but also to maintain raised water tables during summer months when rainfall totals are low. As a result, aquatic losses were determined using a mixture of water mass balance approaches (e.g. using flux tower evapotranspiration data) and groundwater flow monitoring. The hydrology of the 11 sites was found to vary considerably, even between co-located sites, however as might be expected given the west-east rainfall gradient observed in the UK, discharge was typically highest at the Anglesey Fens sites (western Wales) and lowest at the East Anglian Fens sites (eastern England). One influence on the observed differences in discharge was the impact of vegetation type on evapotranspiration rates, with sites with high ET having some of the lowest discharge. Compared to gaseous fluxes, aquatic carbon fluxes made a smaller but significant contribution to overall rates of carbon loss, with the ‘reactive’ aquatic C flux accounting for 2-26% of NEE. Dissolved organic carbon (DOC) made the largest contribution. Concentrations of DOC were generally high, with all sites having mean concentrations greater than 20 mg L-1. DOC fluxes ranged from just 4 g C m-2 yr-1 up to 67 g C m-2 yr-1 being more variable than concentrations due to the wide variation in discharge from the different sites. Fluxes were highest from the raised bog sites and lowest from the fen site