658 research outputs found
Hypersonic research engine project. Phase 2: Aerothermodynamic Integration Model (AIM) data reduction computer program, data item no. 54.16
The data reduction program used to analyze the performance of the Aerothermodynamic Integration Model is described. Routines to acquire, calibrate, and interpolate the test data, to calculate the axial components of the pressure area integrals and the skin function coefficients, and to report the raw data in engineering units are included along with routines to calculate flow conditions in the wind tunnel, inlet, combustor, and nozzle, and the overall engine performance. Various subroutines were modified and used to obtain species concentrations and transport properties in chemical equilibrium at each of the internal and external engine stations. It is recommended that future test plans include the configuration, calibration, and channel assignment data on a magnetic tape generated at the test site immediately before or after a test, and that the data reduction program be designed to operate in a batch environment
Hypersonic research engine project. Phase 2: Some combustor test results of NASA aerothermodynamic integration model
Combustor test results of the NASA Aerothermodynamic Integration Model are presented of a ramjet engine developed for operation between Mach 3 and 8. Ground-based and flight experiments which provide the data required to advance the technology of hypersonic air-breathing propulsion systems as well as to evaluate facility and testing techniques are described. The engine was tested with synthetic air at Mach 5, 6, and 7. The hydrogen fuel was heated to 1500 R prior to injection to simulate a regeneratively cooled system. Combustor efficiencies up to 95 percent at Mach 6 were achieved. Combustor process in terms of effectiveness, pressure integral factor, total pressure recovery and Crocco's pressure-area relationship are presented and discussed. Interactions between inlet-combustor, combustor stages, combustor-nozzle, and the effects of altitude, combustor step, and struts are observed and analyzed
High-sensitivity cardiac troponin T and copeptin assays to improve diagnostic accuracy of exercise stress test in patients with suspected coronary artery disease
Background: The average diagnostic sensitivity of exercise stress tests (ESTs) is lower than that of other non-invasive cardiac stress tests. The aim of the study was to examine whether high-sensitivity cardiac troponin T (hs-cTnT) or copeptin concentrations rise in response to inducible myocardial ischaemia and may improve the diagnostic accuracy of ESTs.
Methods and results: An EST was performed stepwise on a bicycle ergometer by 383 consecutive patients with suspected or progression of coronary artery disease (CAD). In addition venous blood samples for measurement of hs-cTnT and copeptin were collected prior to EST, at peak exercise, and 4 h after EST. Coronary angiography was assessed for all patients. Patients with significant CAD (n=224) were more likely to be male and older compared to patients with non-significant CAD (n=169). Positive EST was documented in 125 (55.8%) patients with significant CAD and in 69 (43.4%) patients with non-significant CAD. Copeptin and hs-cTnT concentrations at baseline were higher in patients with significant CAD (copeptin: 10.8 pmol/l (interquartile range (IQR) 8.115.6) vs 9.4 pmol/l (IQR 7.113.9); p=0.04; hs-cTnT: 3.0 ng/l (IQR <3.05.4) vs <3.0 ng/l (IQR <3.0); p=0.006). Hs-cTnT improved sensitivity (61.6% vs 55.8%), specificity (67.7% vs 56.6%) and the positive predictive value (PPV) (72.3% vs 64.4%) and negative (55.2% vs 47.6%) predictive value (NPV) of EST. Copeptin could not improve sensitivity (55.4% vs 55.8%) and reduced specificity, PPV and NPV.
Conclusions: The measurement of hs-cTnT during EST improves sensitivity, specificity, and positive and negative predictive values. In contrast, measurement of copeptin does not improve diagnostic sensitivity and reduces specificity
Theoretical study of dark resonances in micro-metric thin cells
We investigate theoretically dark resonance spectroscopy for a dilute atomic
vapor confined in a thin (micro-metric) cell. We identify the physical
parameters characterizing the spectra and study their influence. We focus on a
Hanle-type situation, with an optical irradiation under normal incidence and
resonant with the atomic transition. The dark resonance spectrum is predicted
to combine broad wings with a sharp maximum at line-center, that can be singled
out when detecting a derivative of the dark resonance spectrum. This narrow
signal derivative, shown to broaden only sub-linearly with the cell length, is
a signature of the contribution of atoms slow enough to fly between the cell
windows in a time as long as the characteristic ground state optical pumping
time. We suggest that this dark resonance spectroscopy in micro-metric thin
cells could be a suitable tool for probing the effective velocity distribution
in the thin cell arising from the atomic desorption processes, and notably to
identify the limiting factors affecting desorption under a grazing incidence.Comment: 12 pages, 11 figures theoretical articl
Sex Disparities in the Treatment and Control of Cardiovascular Risk Factors in Type 2 Diabetes
OBJECTIVE—To assess whether sex differences exist in the effective control and medication treatment intensity of cardiovascular disease (CVD) risk factors
Testing the Higgs Mechanism in the Lepton Sector with multi-TeV e+e- Collisions
Multi-TeV e+e- collisions provide with a large enough sample of Higgs bosons
to enable measurements of its suppressed decays. Results of a detailed study of
the determination of the muon Yukawa coupling at 3 TeV, based on full detector
simulation and event reconstruction, are presented. The muon Yukawa coupling
can be determined with a relative accuracy of 0.04 to 0.08 for Higgs bosons
masses from 120 GeV to 150 GeV, with an integrated luminosity of 5 inverse-ab.
The result is not affected by overlapping two-photon background.Comment: 6 pages, 2 figures, submitted to J Phys G.: Nucl. Phy
Cost-Effectiveness of Intensified Versus Conventional Multifactorial Intervention in Type 2 Diabetes: Results and projections from the Steno-2 study
OBJECTIVE—To assess the cost-effectiveness of intensive versus conventional therapy for 8 years as applied in the Steno-2 study in patients with type 2 diabetes and microalbuminuria
Insights into the Second Law of Thermodynamics from Anisotropic Gas-Surface Interactions
Thermodynamic implications of anisotropic gas-surface interactions in a
closed molecular flow cavity are examined. Anisotropy at the microscopic scale,
such as might be caused by reduced-dimensionality surfaces, is shown to lead to
reversibility at the macroscopic scale. The possibility of a self-sustaining
nonequilibrium stationary state induced by surface anisotropy is demonstrated
that simultaneously satisfies flux balance, conservation of momentum, and
conservation of energy. Conversely, it is also shown that the second law of
thermodynamics prohibits anisotropic gas-surface interactions in "equilibrium",
even for reduced dimensionality surfaces. This is particularly startling
because reduced dimensionality surfaces are known to exhibit a plethora of
anisotropic properties. That gas-surface interactions would be excluded from
these anisotropic properties is completely counterintuitive from a causality
perspective. These results provide intriguing insights into the second law of
thermodynamics and its relation to gas-surface interaction physics.Comment: 28 pages, 11 figure
Membranes by the Numbers
Many of the most important processes in cells take place on and across
membranes. With the rise of an impressive array of powerful quantitative
methods for characterizing these membranes, it is an opportune time to reflect
on the structure and function of membranes from the point of view of biological
numeracy. To that end, in this article, I review the quantitative parameters
that characterize the mechanical, electrical and transport properties of
membranes and carry out a number of corresponding order of magnitude estimates
that help us understand the values of those parameters.Comment: 27 pages, 12 figure
Prospectus, March 7, 1984
CONGRESS RETURNS TO A \u27MOST IMPORTANT\u27 STUDENT AID DEBATE; News Digest; Four paintings stolen from Parkland; \u27Job Training and Partnership Act\u27: JTPA \u27good opportunity for dedicated\u27; PC Happenings: TV programs for busy parents, Parkland announces registration, Polish folk arts at Parkland; Sargent talks to Lifelong Learners\u27 Club; Yaxley scholarship; Stu-Go News; \u27Planned Parenthood\u27--pro choice organization; In the Library--Paperbacks; Nolen enjoys differences; What is Sadie Hawkins Day?; Did You Know...; Scholarship news for real estate students; Tuexdo styles are changing; What did you thinnk of the Grammy Awards?; Classifieds; \u27Good looking coed\u27 hunt draws lots of photos; Urbana construction will increase; Learning to relax can kill stress; \u27Women\u27s History Week\u27 honored; Parkland Christian Fellowship to sponsor conference; Weather conditions force closing; Math contest at Parkland; Financia; aid for summer and fall; The latest in swimwear; \u27Western look\u27 changing; Creative Corner...Especially for you!!: Believe..., Creed, Dream, The End, Darkness...; All Up to Me, Listening to an old..., Father to Son, How to know just what is real..., For Larry, Hi, I\u27m crazy ...; Bite the Bullet, Answer, Why can\u27t we see?, Love sparked nu the heat of summer...,Keg, A low rumble starts..., Oh, Mothers..., Has the human race forgot to look at a sunset..., I tried to play your game..., You\u27ve let me down...; Jackson leads the way at this year\u27s Grammy awards; Dexter--valuable asset; $50,000 and silence \u27cheap way for MSU to avoid lawsuit\u27; In the Library--; Channel 12 fund drive stresses \u27TV worth paying for\u27; Woody Allen\u27s latest hilarious; \u27Foghat\u27 hits C/U March 18; Predictions for the upcoming Academy Awards; \u27Big Country\u27 to appear; \u27Full Metal Jacket\u27 talent search; \u27The Right Stuff\u27 finally opens in area; Energetic movie should do well; Baseball Schedule; Bank president--NFL referee; High School Notes; Softball Schedule; Cobra baseball to start; Women win tournament; Lake Land advances in sectional; Mens basketball scores; I.M. News; Cobra men advance to sectional; Cobras end up with last year\u27s record; Tae Kwon Do showed display; Cooper remembers 6 good years; First basketball coach tells how it was; NJCAA meethttps://spark.parkland.edu/prospectus_1984/1029/thumbnail.jp
- …