Aerodynamics of advanced axial-flow turbomachinery

A multi-task research program on aerodynamic problems in advanced axial-flow turbomachine configurations was carried out at Iowa State University. The elements of this program were intended to contribute directly to the improvement of compressor, fan, and turbine design methods. Experimental efforts in intra-passage flow pattern measurements, unsteady blade row interaction, and control of secondary flow are included, along with computational work on inviscid-viscous interaction blade passage flow techniques. This final report summarizes the results of this program and indicates directions which might be taken in following up these results in future work. In a separate task a study was made of existing turbomachinery research programs and facilities in universities located in the United States. Some potentially significant research topics are discussed which might be successfully attacked in the university atmosphere

Tracking ground state Ba+ ions in an expanding laser–plasma plume using time-resolved vacuum ultraviolet photoionization imaging

We report results from a study of the integrated column density and expansion dynamics of ground-state-selected Ba+ ions in a laser–plasma plume using a new experimental system—VPIF (vacuum-ultraviolet photoabsorption imaging facility). The ions are tracked by recording the attenuation of a pulsed and collimated vacuum ultraviolet beam, tuned to the 5p–6d inner-shell resonance of singly ionized barium, as the expanding plasma plume moves across it. The attenuated beam is allowed to fall on a CCD array where the spatial distribution of the absorption is recorded. Time-resolved ion velocity and integrated column density maps are readily extracted from the photoionization images

Application of blade-element techniques to design and performance prediction problems for axial-flow turbomachinery Progress report, 1 Apr. - 30 Sep. 1969

Noncavitating operation data from different axial flow pump rotor configurations and correlation of flow pump deviation angle

Study of a colliding laser-produced plasma by analysis of time and space-resolved image spectra

The interaction of two counter-propagating laser-produced plasmas was studied using simultaneous imaging and spectroscopic techniques. Spectrally-filtered time-gated ICCD imaging was used to obtain information about the spatial dynamics and temporal evolution of the collision process. While, time-resolved imaging spectroscopy was used to determine the spatial and temporal distributions of electron temperature and density within the interaction region. We examine specifically the interaction of plasmas whose parameters match those typically used in pulsed laser deposition of thin films. These low temperature plasmas are highly collisional leading to the creation of a pronounced stagnation layer in the interaction region

Viewpoint: A response to Screening and isolation to control methicillin-resistant Staphylococcus aureus: Sense, nonsense, and evidence

Surveillance and isolation for the prevention of methicillin-resistant Staphylococcus aureus (MRSA) has become a controversial topic, one that causes heated debate and appears to be surrounded by both politics and industrial conflicts-of-interest. There have been calls from numerous authors for a movement away from rigid mandates and toward an evidence-based medicine approach. However, much of the evidence can be viewed with an entirely different interpretation. Two major studies with negative findings have had an adverse impact on recommendations regarding active detection and isolation (ADI) for MRSA. However the negative findings in these studies can be explained by shortcomings in study implementation rather than the ineffectiveness of ADI. The use of daily chlorhexidine bathing has also been proposed as an alternative to ADI in ICU settings. There are shortcomings regarding the evidence in the literature concerning the effectiveness of daily chlorhexidine bathing. One of the major concerns with universal daily chlorhexidine bathing is the development of bacterial resistance. The use of surveillance and isolation to address epidemics and common dangerous pathogens should solely depend upon surveillance and isolation\u27s ability to prevent further spread to and infection of other patients through indirect contact. At present, there is a preponderance of evidence in the literature to support continuing use of surveillance and isolation to prevent the spread of MRSA

The Relationship Between Tort Reform and Medical Utilization

NTRODUCTION: The hidden cost of defensive medicine has been cited by policymakers as a significant driving force in the increase of our nation\u27s health-care costs. If this hypothesis is correct, one would expect that states with higher levels of tort reform will have a decrease in Medicare utilization and that medical utilization will decrease after tort reform is enacted. METHODS: State-level reimbursement data for years 1999 to 2010 (the last year available) was obtained from the Dartmouth Atlas of Health Care. Medical tort rankings for the 50 states were obtained from the Pacific Research Institute (PRI) and correlated with state medical utilization for the year 2010. In 3 states, Mississippi, Nevada, and Texas, data were available to make pretort and posttort reform comparisons. RESULTS: Data analysis between total state Medicare Reimbursements and the PRI\u27s tort rankings showed no significant observed correlation. In 6 Medicare utilization categories (total Medicare, hospital and skilled nursing facility, physician, home health agency, hospice, and durable medical equipment), a negative trend was observed when correlated with PRI tort rankings. This trend does not support the hypothesis that defensive medicine is a major driver of health-care expenditures. Tracking expenditures in the states of Texas, Nevada, and Mississippi, before and after passage of comprehensive medical tort reform gave inconsistent results and did not demonstrate substantial or meaningful total Medicare savings. In Mississippi, there was a trend of decreased expenditures after medical tort reform was passed. However, in Texas, where 80% of the analyzed enrollees resided, there was a trend of progressive increasing expenditures after tort reform was passed. CONCLUSION: The comparison of the Dartmouth Atlas Medicare Reimbursement Data with Malpractice Reform State Rankings, which are used by the PRI, did not support the hypothesis that defensive medicine is a driver of rising health-care costs. Additionally, comparing Medicare reimbursements, premedical and postmedical tort reform, we found no consistent effect on health-care expenditures. Together, these data indicate that medical tort reform seems to have little to no effect on overall Medicare cost savings

Batrachochytrium dendrobatidis Detected in Amphibians from National Forests in Eastern Texas, USA

The amphibian disease chytridiomycosis, caused by the pathogenic fungus Batrachochytrium dendrobatidis (Bd, Longcore et al. 1999), is well known as a major threat to amphibians resulting in mass die-offs and population declines throughout the world (Berger et al. 1998; Blaustein and Keisecker 2002; Daszak et al. 2003; McCallum 2005; Rachowicz et al. 2006). Batrachochytrium dendrobatidis has been detected on amphibians from sites across North America (Ouellet et al. 2005; Woodhams et al. 2008) and appears to be most prevalent in the western and the northeastern United States (Longcore et al. 2007; Schlaepfer et al. 2007). Whereas infected anurans also have been found throughout the southeastern US (Green and Dodd 2007), there have been no reports of Bd from amphibians in eastern Texas, a broad area encompassing 10,000,000 ha. We sampled amphibians for the presence of Bd in four National Forests in eastern Texas (approximately 31°N latitude)

Much Work Still to Be Done to Prevent Central Line-Associated Bloodstream Infections

Central Line Associated Bloodstream Infections (CLABSI) are all too common and often fatal events. To estimate the number of preventable CLABSIs, the authors analyzed SIR (Standardized Infection Ratio) and the number of CLABSI data from Hospital Com-pare. Several studies have suggested that an SIR of 0.35 may be achievable. If all institutions were able to perform at this level, then almost 50% of CLABSI would be prevented

On the Existence of an Optimum End-to-side Junctional Geometry in Peripheral Bypass Surgery—A Computer Generated Study

AbstractBackground. To investigate hemodynamic flow changes associated with vein cuffs and patches that may be responsible for improved patency of prosthetic infrainguinal grafts.Methods. The role of the graft–artery junction angle was examined by computational fluid dynamics to assess the influence of anastomotic geometry on wall shear stress (WSS) distributions. Three geometrically different junction configurations were studied and the WSS and WSS gradient (WSSG) values were compared.Results. The inclusion of a patch or a cuff moves the bed stagnation point (BSP) distally, increasing the area on the bed of the junction which experiences a BSP and reducing the strength of the recirculation region opposite the heel of the junction by 54.8 and 50.8%, respectively. The patched geometry promotes earlier recovery of the flow in the distal outflow segment (DOS) than for the unpatched model. Also, the helical flow patterns in the DOS associated with the cuffed geometry are stronger. The net effect of these changes are that peak WSSG values for the patched and cuffed geometries are three times lower than those for the uncuffed geometry.Conclusion. This study provides some additional insights into the hemodynamics of graft–artery junction geometry which may influence future clinical practice