Structure and stability of the compressible Stuart vortex

The structure and two- and three-dimensional stability properties of a linear array of compressible Stuart vortices (CSV; Stuart 1967; Meiron et al. 2000) are investigated both analytically and numerically. The CSV is a family of steady, homentropic, two-dimensional solutions to the compressible Euler equations, parameterized by the free-stream Mach number M_∞, and the mass flux _ inside a single vortex core. Known solutions have 0 < M_∞ < 1. To investigate the normal-mode stability of the generally spatially non-uniform CSV solutions, the linear partial-differential equations describing the time evolution of small perturbations to the CSV base state are solved numerically using a normal-mode analysis in conjunction with a spectral method. The effect of increasing M_∞ on the two main classes of instabilities found by Pierrehumbert & Widnall (1982) for the incompressible limit M_∞ → 0 is studied. It is found that both two- and three-dimensional subharmonic instabilities cease to promote pairing events even at moderate M_∞. The fundamental mode becomes dominant at higher Mach numbers, although it ceases to peak strongly at a single spanwise wavenumber. We also find, over the range of ε investigated, a new instability corresponding to an instability on a parallel shear layer. The significance of these instabilities to experimental observations of growth in the compressible mixing layer is discussed. In an Appendix, we study the CSV equations when ε is small and M_∞ is finite using a perturbation expansion in powers of ε. An eigenvalue determining the structure of the perturbed vorticity and density fields is obtained from a singular Sturm–Liouville problem for the stream-function perturbation at O(ε). The resulting small-amplitude steady CSV solutions are shown to represent a bifurcation from the neutral point in the stability of a parallel shear layer with a tanh-velocity profile in a compressible inviscid perfect gas at uniform temperature

Experiments on the flow past a circular cylinder at very high Reynolds number

Measurements on a large circular cylinder in a pressurized wind tunnel at Reynolds numbers from 10^6 to 10^7 reveal a high Reynolds number transition in which the drag coefficient increases from its low supercritical value to a value 0.7 at R = 3.5 × 10^6 and then becomes constant. Also, for R > 3.5 × 10^6, definite vortex shedding occurs, with Strouhal number 0.27

The Impact of Reagan-era Politics on the Federal Medicaid Program

The political future may be difficult to predict with specificity, but surely the level of publicly-sponsored medical care for the poor will be severely reduced in the coming years, leaving millions of poor Americans to rely on the charitable capacity of the nation\u27s health care providers-or simply to go without. What follows is an attempt to support this characterization of Medicaid and its political future. Section I of this article is a description of Medicaid, its structure prior to 1981, and the legal and political history of its development and implementation. In addition to providing the basis for understanding the potential impact of the proposed Medicaid changes, this section will emphasize the impact on the program of its larger political context and its relation to broader social and economic issues-forces that have sustained the program through two decades of controversy, but that have also imposed rather rigid restraints on its development. In Section II of this article, the original Reagan agenda for reordering federal spending priorities is summarized, with particular focus on Medicaid and other health-related programs. This discussion is followed by an analysis of the fate of the Reagan proposals through the political turmoil of the 97th Congress, and the eventual statutory and administrative changes in Medicaid brought about through the first half of the Reagan Administration. Section III assesses the initial impact of these changes and the probable effects on Medicaid for the next several years, as states react to the program changes and funding limitations imposed by the new federal order

The Impact of Reagan-era Politics on the Federal Medicaid Program

The political future may be difficult to predict with specificity, but surely the level of publicly-sponsored medical care for the poor will be severely reduced in the coming years, leaving millions of poor Americans to rely on the charitable capacity of the nation\u27s health care providers-or simply to go without. What follows is an attempt to support this characterization of Medicaid and its political future. Section I of this article is a description of Medicaid, its structure prior to 1981, and the legal and political history of its development and implementation. In addition to providing the basis for understanding the potential impact of the proposed Medicaid changes, this section will emphasize the impact on the program of its larger political context and its relation to broader social and economic issues-forces that have sustained the program through two decades of controversy, but that have also imposed rather rigid restraints on its development. In Section II of this article, the original Reagan agenda for reordering federal spending priorities is summarized, with particular focus on Medicaid and other health-related programs. This discussion is followed by an analysis of the fate of the Reagan proposals through the political turmoil of the 97th Congress, and the eventual statutory and administrative changes in Medicaid brought about through the first half of the Reagan Administration. Section III assesses the initial impact of these changes and the probable effects on Medicaid for the next several years, as states react to the program changes and funding limitations imposed by the new federal order

Recalibrating the War on Terror by Enhancing Development Practices in the Middle East

I takt med stigande oljepriser har ett av Sveriges största odlingsföretag Svegro bestämt sig för att byta ut sitt nuvarande värmesystem. Svegro består idag av växthus på ca 50 000 m2 på Thorslunda gård, Färingsö. Uppvärmningen sker idag med hjälp av oljeeldning samt den värmeenergi som omvandlas från växthuslampor. Det nya värmesystemet kommer att använda sig av ett annat förbränningsalternativ än mineralolja. Detta kommer göra det möjligt för Svegro att sänka sina energikostnader och minska miljöpåverkan genom reducerat koldioxidutsläpp. Kraven som ställs är att det nya värmesystemet ska kunna integreras med det befintliga värmesystemet och samtidigt leva upp till dagens ekologiska krav. Målet med bytet av värmesystem är att sänka energiförsörjningskostnaderna men också att klara av framtida högre ställda krav och miljömålsättningar. För att avgränsa rapporten har tre olika förbränningsalternativ behandlats där alla passar bra med den nuvarande vattenburna värmelösningen. Alternativen består av bioolja, pellets och flis. För att bestämma det bästa alternativet har en jämförelsestudie mellan de olika bränslena gjorts där faktorer som investeringskostnader, miljöpåverkan och bränsleeffektivitet beaktats. Utifrån analyserna av resultaten i rapporten föreslås pellets som det bäst lämpade systemet för Svegros anläggning. Enligt livskostnadsanalysen i rapporten kommer det nya systemet att ha betalat av sig efter 1,5 år och efter det kommer besparingar på ca 5,5 miljoner kr göras per år jämfört med om det befintliga systemet skulle bevaras. Det nya bränslet kommer utöver ekonomiska besparingar även minska CO2-utsläppen med ca 2300 ton per år. Konsekvenserna av att välja pellets som förbränningsalternativ är att man måste kombinera pelletsförbränningen med en biooljeuppvärmning, detta för att växterna ska klara av att överleva extremt kalla vinterdagarna.While the oil price continues to increase, one of Sweden’s largest indoor growing companies Svegro has decided to replace their existing heating system. Svegro is a large green house with an area of approximately 50 000 m2 and is located at Thorslunda gård, Färingsö.The heating system today uses mineral oil and the heat from assimilation lamps. The new system will be using an alternative combustion fuel to the expensive mineral oil. This will make it possible for Svegro to lower their energy costs and reduce their environmental effect by lowering the emissions of carbon oxide.The requirements are that the new heating system should be able to be integrated with the already existing system and at the same time live up to today´s ecological requirements. The goal of replacing the heating system is to reduce the energy costs but also to manage future demands and environmental ambitions. In order to define some limitations for the reports we have chosen three different combustion options where all alternatives fit with the present heating distribution. The combustion options are biological oil, wood pellets and wood chips. To determine the best option a comparison between the different fuels has been done considering factors such as investment costs, environmental impact and fuel efficiency.Based on the analyzed results we suggest that wood pellets will be the most suitable fuel for Svegros facility and heating system. According to the lifecycle cost the new system will have paid off itself after 1,5 years. The savings made each year from changing fuel will be approximately 5,5 million SEK per year compared if the oil still was used. The new fuel will in addition to the financial savings also reduce the carbon dioxide emissions by 2300 tons per year.The consequence of choosing wood pellets as combustion fuel is that you have to combine the pellet burning with biofuel combustion. The combination will make it possible for the plants to survive extremely cold weather conditions during the winter

WCRO Spring 2007

HSUS helps rescue OR cattle Canned hunts get canned in Oregon Buddy recovers from beating Coast Guard comes to rescue Running a-fowl of cruelty laws Legislators praised for positive record on animals West Coast states honorees Legislative Update CA, OR, WA aim to protect calves, pigs How humane is your society? Ranking of WCRO cities Hawaii: anything but paradise for animals (Eric Sakach