Turbulence, combustion, pollutant, and stability characterization of a premixed, step combustor

A two dimensional combustion tunnel was constructed to study a lean premixed turbulent propane/air flame stablized behind a rearward facing step. Studied were: (1) the existence and importance of large coherent structures in turbulent reacting and nonreacting free shear layers behind the steps; (2) the effect of inlet temperature and reference velocity on combustion efficiency; (3) CO, NO2 and NO sub x production in the flame; and (4) the blowout and upstream propagation of the flame. In the ranges studied, the large coherent structures dominated both the reacting and the nonreacting free shear layers behind the step. The growth of the vortices and the propagation of the flamer were intimately linked. Vortex pairing was observed to be one of the mechanisms for introduction of fresh reactants into the shear layer and growth of the shear layer. Probe composition measurements of the flame showed that, in the recirculation zone, the reaction was above 99 percent complete, CO and unburnt hydrocarbons were above the equilibrium level NO sub x concentration was far below the equilibrium level and NO2 comprised a negligible fraction of NO sub x

Leadership effectiveness and its relationship with emotional stability among nurse managers in educational hospitals related to Isfahan University of Medical Science in 2007

زمینه و هدف: تغییرات گسترده ای که امروزه در مؤسسات مراقبت بهداشتی به وقوع پیوسته است ضرورت ترکیب مهارت های رهبری و مدیریت را به وجود آورده است. به علاوه، موفقیت در مراقبت از بیمار و جلب اعتبار بیمارستان تا حد زیادی به شایستگی و علاقه کارکنان پرستاری بستگی دارد. هدف این پژوهش تعیین اثربخشی رهبری و ارتباط آن با ثبات عاطفی در مدیران پرستاری می باشد. روش بررسی: این پژوهش از نوع توصیفی همبستگی بود که در سال 1386 بر روی 128 نفر از مدیران پرستاری بیمارستان های آموزشی وابسته به دانشگاه علوم پزشکی شهر اصفهان با روش نمونه گیری سرشماری انجام شد. ابزار جمع آوری اطلاعات پرسشنامه اصول رهبری اثربخش و پرسشنامه شخصیت کنتل (Kentel) بود. در این پژوهش اثربخشی رهبری و ثبات عاطفی مورد سنجش قرار گرفت. یافته ها: یافته های پژوهش نشان داد که 8/77 مدیران خدمات پرستاری، 7/66 سوپروایزران و 1/72 سرپرستاران مورد پژوهش اثربخشی رهبری قوی داشته اند. همچنین بین اثربخشی رهبری و ثبات عاطفی در رده سوپروایزران همبستگی مستقیم و معنی دار وجود داشت (02/0 = Pو 39/0r=-) اما در سایر رده ها بین اثربخشی رهبری و ثبات عاطفی همبستگی معنی داری مشاهده نشد. نتیجه گیری: نتایج نشان داد بین اثربخشی رهبری و ثبات عاطفی در رده سوپروایزران، ارتباط مستقیمی وجود دارد لذا توجه به ویژگی های شخصیتی در انتخاب این مدیران باید مورد توجه قرار گیرد

Solving Ratio-Dependent Predator-Prey System with Constant Effort Harvesting using Variational Iteration Method

Due to wide range of interest in use of bio-economic models to gain insight into the scientific management of renewable resources like fisheries and forestry,variational iteration method (VIM) is employed to approximate the solution of the ratio-dependent predator-prey system with constant effort prey harvesting.The results are compared with the results obtained by Adomian decomposition method and reveal that VIM is very effective and convenient for solving nonlinear differential equations

Laboratory studies of lean combustion

The fundamental processes controlling lean combustion were observed for better understanding, with particular emphasis on the formation and measurement of gas-phase pollutants, the stability of the combustion process (blowout limits), methods of improving stability, and the application of probe and optical diagnostics for flow field characterization, temperature mapping, and composition measurements. The following areas of investigation are described in detail: (1) axisymmetric, opposed-reacting-jet-stabilized combustor studies; (2) stabilization through heat recirculation; (3) two dimensional combustor studies; and (4) spectroscopic methods. A departure from conventional combustor design to a premixed/prevaporized, lean combustion configuration is attractive for the control of oxides of nitrogen and smoke emissions, the promotion of uniform turbine inlet temperatures, and, possibly, the reduction of carbon monoxide and hydrocarbons at idle

Solving Ratio-Dependent Predator-Prey System with Constant Effort Harvesting Using Homotopy Perturbation Method

Due to wide range of interest in use of bioeconomic models to gain insight into the scientific management of renewable resources like fisheries and forestry, homotopy perturbation method is employed to approximate the solution of the ratio-dependent predator-prey system with constant effort prey harvesting. The results are compared with the results obtained by Adomian decomposition method. The results show that, in new model, there are less computations needed in comparison to Adomian decomposition method

Loss of function mutation in toll-like receptor-4 does not offer protection against obesity and insulin resistance induced by a diet high in trans fat in mice

<p>Abstract</p> <p>Background</p> <p>Toll-like receptor-4 (TLR4) triggers inflammatory signaling in response to microbial lipoploysaccharide. It has been reported that loss of TLR4 protected against saturated fat-induced inflammation and insulin resistance. It is not known whether loss of TLR4 function offers protection against trans fat (TF) induced obesity, inflammation, and insulin resistance. We investigated whether mice with loss of function mutation in TLR4 were resistant to TF-induced pathologies such as obesity, inflammation, hyperglycemia, and hyperinsulinemia.</p> <p>Methods</p> <p>C57BL/6j and C57BL/10 mice were cross bred to generate TLR4 mutant and wild type (WT). TLR4 mutant (n = 12) and WT (n = 12) mice were fed either low fat (LF) (13.5% fat energy) or high TF diets (60% fat energy) for 12 weeks. <it>In vitro </it>experiments were conducted on mouse macrophage cells (RAW 264.7 and J774A.1) to investigate whether elaidic (trans 18:1) or oleic acid (cis 18:1) would upregulate inflammatory markers.</p> <p>Results</p> <p>TLR4 mutant mice were ~26.4% heavier than WT mice. In both genotypes, mice that received TF diet were significantly heavier than those mice that received LF diet (P < 0.01). TLR4 mutant mice compared to WT mice had significantly higher fasting blood glucose, serum insulin, insulin resistance, serum leptin, and serum cholesterol when they received TF diet (P < 0.05). No upregulation of iNOS or COX2 in response to either elaidic or oleic acid in macrophage cells was observed.</p> <p>Conclusions</p> <p>Loss of function mutation in TLR4 not only did not protect mice from TF-induced obesity, hyperglycemia, hyperinsulinemia, and hypercholesterolemia but also exacerbated the above pathologies suggesting that functional TLR4 is necessary in attenuating TF-induced deleterious effects. It is likely that TF induces pathologies through pathways independent of TLR4.</p

Effect of broodstocks numbers on cyst formation of bisexual and parthenogenetic strains of Artemia urmiana habitat

Artemia has important role as live food in aquaculture nutrition. There are bisexual and parthenogenetic strains of Artemia urmiana which are living around the Urmia Lake. Selection of suitable strain for culturing programe must be considered at aquaculture industry. In order to find suitable at both strains for, the evaluation of ovoviviparous and viviparously characteristics must be done. The objective of the present study was to introduce the suitable generation for both characteristics (cyst & nauplii production) in bisexual and parthenogenetic strains of Artemia urmiana at urmia lake, Iran. This research was carried out at laboratory under similar and fixed experimental condition for culture. Each artemia was fed with live Dunaliella tertiolecta species .Adults at each generation were assessed the number for frequency of cyst and nauplii production and mortality rate. Results with using one-way ANOVA &Duncan test by SPSS software were analyzed. The results showed that there is significant difference among 10 generation at bisexual strain of Artemia urmiana for cyst-production and mortality rate (P<0.05) and this variation was not significant for nauplii production.In addition that the seventh generation had high cyst-production and sixth generation had high nauplii-production in bisexual strain. The results showed that there is significant difference among 10 generation for at parthenogenetic strain of Artemia urmiana around urmia lake for cyst and nauplii production and mortality rate (P<0.05). In addition that the seventh generation had high cyst-production and tenth generation had high nauplii-production in parthenogenetic strain. Totally, adults of bisexual strain was suitable for cyst-production and parthenogenetic strain for nauplii-production was suitable. The mortality rate had high at bisexual strain compared to parthenogenetic strain .It can be concluded that the seventh generation for cyst-production were suitable in both strains and sixth generation for nauplii-production in bisexual strain and tenth generation for nauplii-production in parthenogenetic strain were suitable. It is recommended to select seventh generation for cyst-production at both strains and tenth generation for nauplii-production at parthenogenetic strain studied

Effect of broodstocks numbers on cyst formation of bisexual and parthenogenetic strains of Artemia urmiana habitat

Artemia has important role as live food in aquaculture nutrition. There are bisexual and parthenogenetic strains of Artemia urmiana which are living around the Urmia Lake. Selection of suitable strain for culturing programe must be considered at aquaculture industry. In order to find suitable at both strains for, the evaluation of ovoviviparous and viviparously characteristics must be done. The objective of the present study was to introduce the suitable generation for both characteristics (cyst & nauplii production) in bisexual and parthenogenetic strains of Artemia urmiana at urmia lake, Iran. This research was carried out at laboratory under similar and fixed experimental condition for culture. Each artemia was fed with live Dunaliella tertiolecta species .Adults at each generation were assessed the number for frequency of cyst and nauplii production and mortality rate. Results with using one-way ANOVA &Duncan test by SPSS software were analyzed. The results showed that there is significant difference among 10 generation at bisexual strain of Artemia urmiana for cyst-production and mortality rate (P<0.05) and this variation was not significant for nauplii production.In addition that the seventh generation had high cyst-production and sixth generation had high nauplii-production in bisexual strain. The results showed that there is significant difference among 10 generation for at parthenogenetic strain of Artemia urmiana around urmia lake for cyst and nauplii production and mortality rate (P<0.05). In addition that the seventh generation had high cyst-production and tenth generation had high nauplii-production in parthenogenetic strain. Totally, adults of bisexual strain was suitable for cyst-production and parthenogenetic strain for nauplii-production was suitable. The mortality rate had high at bisexual strain compared to parthenogenetic strain .It can be concluded that the seventh generation for cyst-production were suitable in both strains and sixth generation for nauplii-production in bisexual strain and tenth generation for nauplii-production in parthenogenetic strain were suitable. It is recommended to select seventh generation for cyst-production at both strains and tenth generation for nauplii-production at parthenogenetic strain studied

Investigation of Rotating MHD Viscous Flow and Heat Transfer between Stretching and Porous Surfaces Using Analytical Method

Hydromagnetic flow between two horizontal plates in a rotating system, where the lower plate is a stretching sheet and the upper is a porous solid plate, is analyzed. Heat transfer in an electrically conducting fluid bonded by two parallel plates is studied in the presence of viscous dissipation. The equations of conservation of mass and momentum and energy are reduced to a nonlinear ordinary differential equations system. Homotopy perturbation method is used to get complete analytic solution for velocity and temperature profiles. Results show an acceptable agreement between this method results and numerical solution. Also the effects of different parameters are discussed through graphs