342 research outputs found
Dimensional analysis of droplet size and ligament length during high-speed rotary bell atomization
Modern spray-coating processes are based on high-volume, low-pressure, airless atomization or high-speed rotary bell atomization, often assisted by electrostatic charging to increase the transfer efficiency. The process from the liquid film flow beneath the bell, through ligament formation and consecutive disintegration to droplet deposition, has been constantly explored during the evolution of automotive spray coating. This work proposes a set of dimensionless groups that fully describe the process from film flow to ligament disintegration, including shear and elongational flow effects during atomization of particle laden, shear thinning, viscoelastic fluids
Dimensional analysis of droplet size and ligament length during high-speed rotary bell atomization
Modern spray-coating processes are based on high-volume, low-pressure, airless atomization or high-speed rotary bell atomization, often assisted by electrostatic charging to increase the transfer efficiency. The process from the liquid film flow beneath the bell, through ligament formation and consecutive disintegration to droplet deposition, has been constantly explored during the evolution of automotive spray coating. This work proposes a set of dimensionless groups that fully describe the process from film flow to ligament disintegration, including shear and elongational flow effects during atomization of particle laden, shear thinning, viscoelastic fluids
Analysis of Paint Flow Pulsations during High-Speed Rotary Bell Atomization
High-speed rotary bell atomization is the preeminent coating technique in the automotive industry. It is widely accepted that a narrow droplet size distribution and constant spray are necessary in order to guarantee uniform film thickness and high-quality appearance. This may be deteriorated by paint flow pulsations. So far, however, no studies exist regarding such fluctuations quantitatively for this type of atomizers. We fill this gap using image analysis of high-speed recordings close to the bell edge. We could show that the fundamental pulsation frequency increases linearly with rotational speed. A ratio of pulsation frequency and true rotational speed of about 3 was found, indicating that pulsations were initiated mainly by the three struts of the distributor disc. The coefficient of variation, i.e., the amplitude of fluctuation increased with decreasing liquid volume rate and rotational speed. Beyond that, we could show that the formation of droplets larger than 100 ÎŒm, which are assumed to cause paint defects, is promoted by the degree of fluctuation. These findings may stimulate development of bell cups showing less paint flow pulsations
Associations between MTHFR 1793G>A and plasma total homocysteine, folate, and vitamin B12 in kidney transplant recipients
Associations between MTHFR 1793G>A and plasma total homocysteine, folate, and vitamin B12 in kidney transplant recipients.BackgroundCurrently, no evidence is available on the putative associations between a novel single nucleotide polymorphism of the 5,10-methylenetetrahydrofolate reductase gene MTHFR 1793G>A and plasma levels of vitamin B12, folate, or total homocysteine (tHcy).MethodsIn a cross-sectional study of 730 kidney allograft recipients, patients were categorized by MTHFR 1793G>A genotype. In univariate and multivariate linear regression models that allowed the outcome variables vitamin B12, folate, and tHcy plasma levels to follow a gamma distribution, we tested for possible associations of allelic variants of MTHFR 1793G>A and these three dependent variables. As hypothesized in previous work, we specifically evaluated possible effect modification between the MTHFR 1793G>A and 1298A>C mutations on these outcomes.ResultsThe allele frequency for MTHFR 1793G>A was 0.052. Heterozygosity (N = 72) or homozygosity (N = 2) for MTHFR 1793G>A was not independently associated with plasma levels of vitamin B12 (P = 0.33) or tHcy (P = 0.70), but a borderline association with higher folate concentrations was detected (Îfolate = 1.91 nmol/L) (95% CI -0.03 to 3.86 nmol/L) (P = 0.05). Further, we found strong and significant positive interactions between the MTHFR 1793G>A and 1298A>C mutations on vitamin B12 concentrations.ConclusionHigher folate concentrations in kidney transplant recipients with MTHFR 1793GA or 1793AA and markedly higher concentrations of vitamin B12 in patients with combined MTHFR 1793G>A and 1298A>C mutations may contribute to the survival advantage that has been postulated for such patients showing these genotypes
Challenges and opportunities for quantifying roots and rhizosphere interactions through imaging and image analysis
The morphology of roots and root systems influences the efficiency by which plants acquire nutrients and water, anchor themselves and provide stability to the surrounding soil. Plant genotype and the biotic and abiotic environment significantly influence root morphology, growth and ultimately crop yield. The challenge for researchers interested in phenotyping root systems is, therefore, not just to measure roots and link their phenotype to the plant genotype, but also to understand how the growth of roots is influenced by their environment. This review discusses progress in quantifying root system parameters (e.g. in terms of size, shape and dynamics) using imaging and image analysis technologies and also discusses their potential for providing a better understanding of root:soil interactions. Significant progress has been made in image acquisition techniques, however trade-offs exist between sample throughput, sample size, image resolution and information gained. All of these factors impact on downstream image analysis processes. While there have been significant advances in computation power, limitations still exist in statistical processes involved in image analysis. Utilizing and combining different imaging systems, integrating measurements and image analysis where possible, and amalgamating data will allow researchers to gain a better understanding of root:soil interactions
Farewell, welfare state â hello, welfare regions? Chances and constraints of welfare management in the German federal system
The German welfare state is in crisis. Alarming long-term demographic trends, the still not fully digested consequences of German unification and the current economic downturn in much of the Eurozone have combined to create an urgent need for welfare reform. Yet the constitutional arrangements which govern the German political system, and well-entrenched political practice, mean that any such reform process is a daunting challenge. Thus, the welfare crisis is also a crisis of German-style co-operative federalism. Current empirical evidence makes for uncomfortable reading, and triggers debate on the nature of the German federation: have the two constitutional principles of federalism and establishing equal living conditions throughout the federation become mutually exclusive? However, as much of the welfare state is centred on the best utilisation of scarce financial resources, it is debatable to what extent alterations in the functional distribution of welfare responsibilities among the territorial levels of government can be regarded as a solution for the current problems. The article concludes that in the search for long-term sustainability of the welfare state the territorial dimension is likely to remain a secondary issue
Interferometric synthetic aperture radar-GPS integration: Interseismic strain accumulation across the Hunter Mountain fault in the eastern California shear zone
Mountain fault in the eastern California shear zon
S. <i>mansoni</i> Schistosomula Antigens Induce Th1/Proinflammatory Cytokine Responses
Larvae of Schistosoma (schistosomula) are highly susceptible to host immune responses and are attractive prophylactic vaccine targets, although cellular immune responses against schistosomula antigens in endemic human populations are not well characterized. We collected blood and stool from 54 Schistosoma mansoni-infected Ugandans, isolated peripheral blood mononuclear cells and stimulated them for 24Â hours with schistosome adult worm and soluble egg antigens (AWA and SEA), along with schistosomula recombinant proteins rSmKK7, Lymphocyte Antigen 6 isoforms (rSmLy6A and rSmLy6B), tetraspanin isoforms (rSmTSP6 and rSmTSP7). Cytokines, chemokines and growth factors were measured in the culture supernatants using a multiplex luminex assay, and infection intensity was determined before and at 1Â year after praziquantel (PZQ) treatment using the Kato-Katz method. Cellular responses were grouped and the relationship between groups of correlated cellular responses and infection intensity before and after PZQ treatment was investigated. AWA and SEA induced mainly Th2 responses. In contrast, rSmLy6B, rSmTSP6 and rSmTSP7 induced Th1/pro-inflammatory responses. While recombinant antigens rSmKK7 and rSmLy6A did not induce a Th1/pro-inflammatory response, they had an association with pre-treatment infection intensity after adjusting for age and sex. Testing more schistosomula antigens using this approach could provide immune-epidemiology identifiers necessary for prioritizing next generation schistosomiasis vaccine candidates
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