Critical review of the trailing edge condition in steady and unsteady flow. Blade flutter in compressors and fans: Numerical simulation of the aerodynamic loading

Existing interpretations of the trailing edge condition, addressing both theoretical and experimental works in steady, as well as unsteady flows are critically reviewed. The work of Kutta and Joukowski on the trailing edge condition in steady flow is reviewed. It is shown that for most practical airfoils and blades (as in the case of most turbomachine blades), this condition is violated due to rounded trailing edges and high frequency effects, the flow dynamics in the trailing edge region being dominated by viscous forces; therefore, any meaningful modelling must include viscous effects. The question of to what extent the trailing edge condition affects acoustic radiation from the edge is raised; it is found that violation of the trailing edge condition leads to significant sound diffraction at the tailing edge, which is related to the problem of noise generation. Finally, various trailing edge conditions in unsteady flow are discussed, with emphasis on high reduced frequencies

Simulation of Demographic Change in Palestinian Territories

Mortality, birth rates and retirement play a major role in demographic changes. In most cases, mortality rates decreased in the past century without noticeable decrease in fertility rates, this leads to a significant increase in population growth. In many poor countries like Palestinian territories the number of births has fallen and the life expectancy increased. In this article we concentrate on measuring, analyzing and extrapolating the age structure in Palestine a few decades ago into future. A Fortran program has been designed and used for the simulation and analysis of our statistical data. This study of demographic change in Palestine has shown that Palestinians will have in future problems as the strongest age cohorts are the above-60-year olds. We therefore recommend the increase of both the retirement age and women employment.Comment: For Int. J. Mod. Phys. C 18, issue 11; 9 pages including figures and progra

Immunogenetic novelty confers a selective advantage in host–pathogen coevolution

The major histocompatibility complex (MHC) is crucial to the adaptive immune response of vertebrates and is among the most polymorphic gene families known. Its high diversity is usually attributed to selection imposed by fast-evolving pathogens. Pathogens are thought to evolve to escape recognition by common immune alleles, and, hence, novel MHC alleles, introduced through mutation, recombination, or gene flow, are predicted to give hosts superior resistance. Although this theoretical prediction underpins host–pathogen “Red Queen” coevolution, it has not been demonstrated in the context of natural MHC diversity. Here, we experimentally tested whether novel MHC variants (both alleles and functional “supertypes”) increased resistance of guppies (Poecilia reticulata) to a common ectoparasite (Gyrodactylus turnbulli). We used exposure-controlled infection trials with wild-sourced parasites, and Gyrodactylus-naïve host fish that were F2 descendants of crossed wild populations. Hosts carrying MHC variants (alleles or supertypes) that were new to a given parasite population experienced a 35–37% reduction in infection intensity, but the number of MHC variants carried by an individual, analogous to heterozygosity in single-locus systems, was not a significant predictor. Our results provide direct evidence of novel MHC variant advantage, confirming a fundamental mechanism underpinning the exceptional polymorphism of this gene family and highlighting the role of immunogenetic novelty in host–pathogen coevolution

A cost effectiveness analysis of salt reduction policies to reduce coronary heart disease in four Eastern Mediterranean countries.

BACKGROUND: Coronary Heart Disease (CHD) is rising in middle income countries. Population based strategies to reduce specific CHD risk factors have an important role to play in reducing overall CHD mortality. Reducing dietary salt consumption is a potentially cost-effective way to reduce CHD events. This paper presents an economic evaluation of population based salt reduction policies in Tunisia, Syria, Palestine and Turkey. METHODS AND FINDINGS: Three policies to reduce dietary salt intake were evaluated: a health promotion campaign, labelling of food packaging and mandatory reformulation of salt content in processed food. These were evaluated separately and in combination. Estimates of the effectiveness of salt reduction on blood pressure were based on a literature review. The reduction in mortality was estimated using the IMPACT CHD model specific to that country. Cumulative population health effects were quantified as life years gained (LYG) over a 10 year time frame. The costs of each policy were estimated using evidence from comparable policies and expert opinion including public sector costs and costs to the food industry. Health care costs associated with CHDs were estimated using standardized unit costs. The total cost of implementing each policy was compared against the current baseline (no policy). All costs were calculated using 2010 PPP exchange rates. In all four countries most policies were cost saving compared with the baseline. The combination of all three policies (reducing salt consumption by 30%) resulted in estimated cost savings of $235,000,000 and 6455 LYG in Tunisia;$39,000,000 and 31674 LYG in Syria; $6,000,000 and 2682 LYG in Palestine and$1,3000,000,000 and 378439 LYG in Turkey. CONCLUSION: Decreasing dietary salt intake will reduce coronary heart disease deaths in the four countries. A comprehensive strategy of health education and food industry actions to label and reduce salt content would save both money and lives

Moisture sensitivity of crumb rubber modified modifier warm mix asphalt additive for two different compaction temperatures

Crumb rubber obtained from scrap tires has been incorporated with asphalt binder to improve the performance of asphalt mixtures in the past decades. Pavements containing crumbrubber modified (CRM) binders present one major drawback: larger amounts of greenhouse gas emissions are produced as there is rise in the energy consumption at the asphalt plant due to the higher viscosity of these type of binders compared with a conventional mixture. The objective of this paper is to calculate the optimum bitumen content for each percentage and evaluate the moisture sensitivity of crumb rubber modified asphalt at two different compacting temperatures. In this study, crumb rubber modified percentages was 0%, 5%, 10% and 15% from the binder weight, with adding 1.5% warm mix asphalt additive (Sasobit) and crush granite aggregate of 9.5mm Nominal maximum size was used after assessing its properties. Ordinary Portland Cement (OPC) used by 2% from fine aggregate. The wet method was using to mix the CRM with bitumen, the CRM conducted at 177°C for 30 min with 700rpm and Sasobit conducted at 120°C for 10 min with 1000rpm. As a result, from this study the optimum bitumen content (OBC) was increased with increased crumb rubber content. For performance test, it was conducted using the AASHTO T283 (2007): Resistance of Compacted Bituminous Mixture to Moisture-Induced Damage. The result was as expected and it was within the specification of the test, the result show that the moisture damage increased with increased the crumb rubber content but it is not exceeding the limit of specification 80% for indirect tension strength ratio (ITSR). For the temperature was with lowing the temperature the moisture damage increased

On folding of fuzzy dynamical chaotic manifold

In this paper, we introduce some types of fuzzy dynamical chaotic manifold .We will also introduce a new type of folding, which is applied to fuzzy dynamical chaotic manifold and we will study the relation between the geometric folding and the chaotic folding of fuzzy dynamical chaotic manifold into itself. And the fuzzy dynamical chaotic manifold will be an achieved deduced

Metformin reduces airway glucose permeability and hyperglycaemia-induced Staphylococcus aureus load independently of effects on blood glucose

Background Diabetes is a risk factor for respiratory infection, and hyperglycaemia is associated with increased glucose in airway surface liquid and risk of Staphylococcus aureus infection. Objectives To investigate whether elevation of basolateral/blood glucose concentration promotes airway Staphylococcus aureus growth and whether pretreatment with the antidiabetic drug metformin affects this relationship. Methods Human airway epithelial cells grown at air–liquid interface (±18 h pre-treatment, 30 μM–1 mM metformin) were inoculated with 5×105 colony-forming units (CFU)/cm2 S aureus 8325-4 or JE2 or Pseudomonas aeruginosa PA01 on the apical surface and incubated for 7 h. Wild-type C57BL/6 or db/db (leptin receptor-deficient) mice, 6–10 weeks old, were treated with intraperitoneal phosphate-buffered saline or 40 mg/kg metformin for 2 days before intranasal inoculation with 1×107 CFU S aureus. Mice were culled 24 h after infection and bronchoalveolar lavage fluid collected. Results Apical S aureus growth increased with basolateral glucose concentration in an in vitro airway epithelia–bacteria co-culture model. S aureus reduced transepithelial electrical resistance (RT) and increased paracellular glucose flux. Metformin inhibited the glucose-induced growth of S aureus, increased RT and decreased glucose flux. Diabetic (db/db) mice infected with S aureus exhibited a higher bacterial load in their airways than control mice after 2 days and metformin treatment reversed this effect. Metformin did not decrease blood glucose but reduced paracellular flux across ex vivo murine tracheas. Conclusions Hyperglycaemia promotes respiratory S aureus infection, and metformin modifies glucose flux across the airway epithelium to limit hyperglycaemia-induced bacterial growth. Metformin might, therefore, be of additional benefit in the prevention and treatment of respiratory infection

Sinteza i biološko djelovanje novih 1-benzil i 1-benzoil 3-heterocikličkih derivata indola

Starting from 1-benzyl- (2a) and 1-benzoyl-3-bromoacetyl indoles (2b) new heterocyclic, 2-thioxoimidazolidine (4a,b), imidazolidine-2,4-dione (5a,b), pyrano(2,3-d)imidazole (8a,b and 9a,b), 2-substituted quinoxaline (11a,b–17a,b) and triazolo(4,3-a)quinoxaline derivatives (18a,b and 19a,b) were synthesized and evaluated for their antimicrobial and anticancer activities. Antimicrobial activity screening performed with concentrations of 0.88, 0.44 and 0.22 g mm2 showed that 3-(1-substituted indol-3-yl)quinoxalin-2(1H)ones (11a,b) and 2-(4-methyl piperazin-1-yl)-3-(1-substituted indol-3-yl) quinoxalines (15a,b) were the most active of all the tested compounds towards P. aeruginosa, B. cereus and S. aureus compared to the reference drugs cefotaxime and piperacillin, while 2-chloro-3-(1-substituted indol-3-yl)quinoxalines (12a,b) were the most active against C. albicans compared to the reference drug nystatin. On the other hand, 2-chloro-3-(1-benzyl indol-3-yl) quinoxaline (12a) display potent efficacy against ovarian cancer xenografts in nude mice with tumor growth suppression of 100 0.3 %.U radu je opisana sinteza, antimikrobno i antitumorsko djelovanje heterocikličkih derivata indola. Polazeći iz 1-benzil- i 1-benzoil-3-bromacetil indola (2a i 2b) sintetizirani su novi heterociklički spojevi 2-tioksoimidazolidini (4a,b), imidazolidin-2,4-dioni (5a,b), pirano(2,3-d)imidazoli (8a,b i 9a,b), 2-supstituirani kinoksalini (11a,b–17a,b) i triazolo(4,3-a)kinoksalini (18a,b i 19a,b). Sintetizirani spojevi testirani su na antimikrobno i antitumorsko djelovanje. Ispitivanje antimikrobnog djelovanja provedeno je s koncentracijama otopina 0,88, 0,44 i 0,22 g mm2 i uspoređeno s referentnim lijekovima cefotaksimom i piperacilinom. Rezultati pokazuju da su 3-(1-supstituirani indol-3-il)kinoksalin-2(1H)oni (11a,b) i 2-(4-metil piperazin-1-il)-3-(1-supstituirani indol-3-il) kinoksalini (15a,b) najaktivniji spojevi na sojeve P. aeruginosa, B. cereus i S. aureus, dok su 2-klor-3-(1-supstituirani indol-3-il)kinoksalini (12a,b) najaktivniji na C. albicans (usporedba s nistatinom). Osim toga, 2-klor-3-(1-benzil indol-3-il) kinoksalin (12a) pokazuje veliku učinkovitost na tumore ovarija miševa (supresija rasta tumora 100 0,3 %)