Drum granulation of NPK fertilizers

Nitrate-based NPK fertilizer was granulated in a bench scale drum granulation unit. The initial fertilizer possessed a particle size distribution similar to those in industrial granulation units. In this work, three factors are identified affecting the degree of fertilizer granulation, these are solution to solid phase ratio, the binder viscosity and the optimal rotation speed of the drum. Experimental results indicate that a critical solution to solid phase ratio is required for an increase in granulation in terms of mass median diameter. The saturated solution viscosity in this system was measured and correlated well to binder viscosity granulation theory with the critical Stokes number calculated at 700. The optimum rotation speed for flighted and unflighted drums correlated with the Froude number relationship for full scale granulation units. (C) 2000 Elsevier Science S.A. All rights reserved.

Granular fertilizer drying and agglomeration in storage

In the manufacture of granular NPK fertilizer the product is cooled before packaging and storage in moisture-proof bags. It has been shown that the temperature of the fertilizer prior to packing is significant in that at high temperatures, drying of the granules takes place in the bag which causes an increase in the humidity of the air surrounding the granules and thus an increase in moisture content at the granule - granule interface. This surface moisture was shown to increase the likelihood of agglomeration in the fertilizer by a capillary adhesion/unconfined yield stress model. An iterative model was set up to establish conditions that would prevent drying occurring, which takes into account fertilizer drying rate, fertilizer cooling rate cooling rate and the effect of coating oils on the drying mechanism.

Integrating field sports, hare population management and conservation

Conflicts between field sports, animal welfare and species conservation are frequently contentious. In Ireland, the Irish Coursing Club (ICC) competitively tests the speed and agility of two greyhounds by using a live hare as a lure. Each coursing club is associated with a number of discrete localities, known as preserves, which are managed favourably for hares including predator control, prohibition of other forms of hunting such as shooting and poaching and the maintenance and enhancement of suitable hare habitat. We indirectly tested the efficacy of such management by comparing hare abundance within preserves to that in the wider countryside. In real terms, mean hare density was 18 times higher, and after controlling for variance in habitat remained 3 times higher, within ICC preserves than the wider countryside. Whilst we cannot rule out the role of habitat, our results suggest that hare numbers are maintained at high levels in ICC preserves either because clubs select areas of high hare density and subsequently have a negligible effect on numbers or that active population management positively increases hare abundance. The Irish hare Lepus timidus hibernicus Bell, 1837 is one of the highest priority species for conservation action in Ireland and without concessions for its role in conservation, any change in the legal status Of hare coursing under animal welfare grounds, may necessitate an increase in Government subsidies for conservation on private land together with a strengthened capacity for legislation enforcement.

Mammals and agri-environment schemes: hare haven or pest paradise?

1. Agri-environment schemes (AESs) are designed to create landscape-scale improvements in biodiversity. While the specific aims of AESs do not always include the enhancement of species of conservation concern, associated conservation strategies, such as the UK Biodiversity Action Plan, often rest on the assumption that AESs enhance environmental conditions and thereby improve the conservation status of target species. However, there is little evidence for the general efficacy of AESs in this respect. 2. To evaluate the effects of the Environmentally Sensitive Area (ESA) scheme, a widespread AES in Northern Ireland, a spotlight survey of the relative abundance of three mammal species, Irish hare Lepus timidus hibernicus, European rabbit Oryctolagus cuniculus and red fox Vulpes vulpes, was conducted. Of these, the Irish hare is a priority species for conservation action and the focus of a species action plan, while rabbit and fox are commonly considered agricultural pests. The effects of ESA designation and habitat on each species were assessed at 150 ESA and 50 non-ESA sites, matched for landscape characteristics. 3. The ESA scheme had no demonstrable effect on the abundance of Irish hares, and this agri-environment scheme did not target the landscape and habitat variables associated with hares. 4. In contrast, the abundance of rabbits and foxes was significantly greater within ESAs than the wider countryside. Agricultural factors such as reduced livestock stocking density, reduced overgrazing and field boundary enhancements may create more favourable conditions for both species. Aside from the implications for farm economics, the proliferation of rabbit populations within conservation areas may raise issues concerning the grazing of important plant communities, while increases in fox populations may adversely affect ground-nesting birds and other animal species of conservation concern. 5. Synthesis and applications: The abundance of rabbits and foxes corroborates recent work that suggests AESs may benefit common species but can not be relied upon to encourage rarer species. The Irish hare species action plan relies on agri-environment schemes to enhance the species’ status and realize the target of increasing the hare population by 2010 by promoting suitable habitat. However, the ESA scheme is unlikely to help in achieving these objectives. Targeted and evidence-based agri-environment prescriptions are clearly required in order to ensure the realization of species-specific conservation targets.

Steady-State and Transient Performance of Biodiesel-Fueled Compression-Ignition-Based Electrical Generation

This paper investigates the performance characteristics of rapeseed methyl ester, EN 14214 biodiesel, when used for electrical generation in compression ignition engines. The work was inspired by the need to replace fossil diesel fuel with a sustainable low carbon alternative while maintaining generator performance, power quality, and compliance with ISO 8528-5. A 50-kVA Perkins diesel engine generator was used to assess the impact of biodiesel with particular regard to gen-set fuel consumption, load acceptance, and associated standards. Tests were performed on the diesel gen-set for islanded and grid-connected modes of operation, hence both steady-state and transient performance were fully explored. Performance comparisons were made with conventional fossil diesel fuel, revealing minimal technical barriers for electrical generation from this sustainable, carbon benign fuel. Recommendations for improved transient performance are proposed and validated through tests.

Genome-wide association study identifies variants at CLU and PICALM associated with Alzheimer's disease

We undertook a two-stage genome-wide association study (GWAS) of Alzheimer's disease (AD) involving over 16,000 individuals, the most powerful AD GWAS to date. In stage 1 (3,941 cases and 7,848 controls), we replicated the established association with the apolipoprotein E (APOE) locus (most significant SNP, rs2075650, P = 1.8 x 10(-157)) and observed genome-wide significant association with SNPs at two loci not previously associated with the disease: at the CLU (also known as APOJ) gene (rs11136000, P = 1.4 x 10(-9)) and 5. to the PICALM gene (rs3851179, P = 1.9 x 10(-8)). These associations were replicated in stage 2 (2,023 cases and 2,340 controls), producing compelling evidence for association with Alzheimer's disease in the combined dataset (rs11136000, P = 8.5 x 10(-10), odds ratio = 0.86; rs3851179, P = 1.3 x 10(-9), odds ratio = 0.86).