36,943 research outputs found

    Realization and efficiency evaluation of a micro-photocatalytic cell prototype for real-time blood oxygenation

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    This paper was presented at the 2nd Micro and Nano Flows Conference (MNF2009), which was held at Brunel University, West London, UK. The conference was organised by Brunel University and supported by the Institution of Mechanical Engineers, IPEM, the Italian Union of Thermofluid dynamics, the Process Intensification Network, HEXAG - the Heat Exchange Action Group and the Institute of Mathematics and its Applications.A novel approach to blood oxygenation is presented. Microfluidic channels molded out of PDMS (using standard soft lithography techniques) work as photocatalytic cells, where the coupling of anatase titanium dioxide (TiO2) thin films and platinum electrodes, allow an electrically assisted photocatalytic reaction to produce dissolved oxygen gas from the water content of the flowing blood. The thin films were deposited onto quartz glass substrates at room temperature (300K) using reactive RF sputtering with a Ti metal target. The results of the current study, as a proof of concept, have shown that the device can generate oxygen at a rate of 4.06×10-3 mM O2/(cm2 min) and oxygenate venous blood to the oxygen saturation level of arterial blood

    Large angle magnetization dynamics measured by time-resolved ferromagnetic resonance

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    A time-resolved ferromagnetic resonance technique was used to investigate the magnetization dynamics of a 10 nm thin Permalloy film. The experiment consisted of a sequence of magnetic field pulses at a repetition rate equal to the magnetic systems resonance frequency. We compared data obtained by this technique with conventional pulsed inductive microwave magnetometry. The results for damping and frequency response obtained by these two different methods coincide in the limit of a small angle excitation. However, when applying large amplitude field pulses, the magnetization had a non-linear response. We speculate that one possible cause of the nonlinearity is related to self-amplification of incoherence, known as the Suhl instabilities.Comment: 23 pages, 8 figures, submitted to PR

    Stability of extemporaneously prepared ophthalmic solutions for mydriasis

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    Purpose Results of an evaluation of the physical and chemical stability of extemporaneously prepared adult and pediatric ophthalmic solutions containing combinations of phenylephrine, tropicamide, and cyclopentolate are reported. Methods A stability study was conducted to help determine the feasibility of innovative formulations to meet an unmet clinical need for combination mydriatic ophthalmic eyedrops. An adult mydriatic ophthalmic solution containing phenylephrine hydrochloride 2.5% and tropicamide 1.0% and a pediatric formulation containing phenylephrine hydrochloride 2.5%, tropicamide 0.5%, and cyclopentolate hydrochloride 0.5% were prepared using proper aseptic techniques. Triplicate samples of each formulation were stored for 60 days at refrigeration temperatures (2–8 °C) and analyzed on day 0 and days 7, 14, 28, and 60. At each time point, the stability samples were assessed by visual inspection, pH measurement, and stability-indicating high-performance liquid chromatography (HPLC) analysis. Results Over the 60-day storage period, there was no significant change in the visual appearance or pH level of any of the adult or pediatric solution samples. The results of HPLC analysis indicated that all samples retained 97–102% of the initial drug concentrations for up to 60 days. Conclusion Both adult and pediatric ophthalmic formulations containing combinations of phenylephrine, tropicamide, and cyclopentolate were stable physically and chemically for up to 60 days when stored at refrigeration temperatures (2–8 °C)

    A Corrosion Control Manual for Rail Rapid Transit

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    This manual addresses corrosion problems in the design, contruction, and maintenance of rapid transit systems. Design and maintenance solutions are provided for each problem covered. The scope encompasses all facilities of urban rapid transit systems: structures and tracks, platforms and stations, power and signals, and cars. The types of corrosion and their causes as well as rapid transit properties are described. Corrosion control committees, and NASA, DOD, and ASTM specifications and design criteria to which reference is made in the manual are listed. A bibliography of papers and excerpts of reports is provided and a glossary of frequently used terms is included

    Gilbert damping and spin Coulomb drag in a magnetized electron liquid with spin-orbit interaction

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    We present a microscopic calculation of the Gilbert damping constant for the magnetization of a two-dimensional spin-polarized electron liquid in the presence of intrinsic spin-orbit interaction. First we show that the Gilbert constant can be expressed in terms of the auto-correlation function of the spin-orbit induced torque. Then we specialize to the case of the Rashba spin-orbit interaction and we show that the Gilbert constant in this model is related to the spin-channel conductivity. This allows us to study the Gilbert damping constant in different physical regimes, characterized by different orderings of the relevant energy scales -- spin-orbit coupling, Zeeman coupling, momentum relaxation rate, spin-momentum relaxation rate, spin precession frequency -- and to discuss its behavior in various limits. Particular attention is paid to electron-electron interaction effects,which enter the spin conductivity and hence the Gilbert damping constant via the spin Coulomb drag coefficient.Comment: 18 pages, 8 figure

    Quenching of pairing gap at finite temperature in 184W

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    We extract pairing gap in 184^{184}W at finite temperature for the first time from the experimental level densities of 183^{183}W, 184^{184}W, and 185^{185}W using "thermal" odd-even mass difference. We found the quenching of pairing gap near the critical temperature Tc=0.47T_c = 0.47 MeV in the BCS calculations. It is shown that the monopole pairing model with a deformed Woods-Saxon potential explains the reduction of the pairing correlation using the partition function with the number parity projection in the static path approximation plus random-phase approximation.Comment: 5 pages, 4 figures, accepted for publication in PR

    Extraction of thermal and electromagnetic properties in 45Ti

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    The level density and gamma-ray strength function of 45Ti have been determined by use of the Oslo method. The particle-gamma coincidences from the 46Ti(p,d gamma)45Ti pick-up reaction with 32 MeV protons are utilized to obtain gamma-ray spectra as function of excitation energy. The extracted level density and strength function are compared with models, which are found to describe these quantities satisfactorily. The data do not reveal any single-particle energy gaps of the underlying doubly magic 40Ca core, probably due to the strong quadruple deformation

    Control-system techniques for improved departure/spin resistance for fighter aircraft

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    Some fundamental information on control system effects on controllability of highly maneuverable aircraft at high angles of attack are summarized as well as techniques for enhancing fighter aircraft departure/spin resistance using control system design. The discussion includes: (1) a brief review of pertinent high angle of attack phenomena including aerodynamics, inertia coupling, and kinematic coupling; (2) effects of conventional stability augmentation systems at high angles of attack; (3) high angle of attack control system concepts designed to enhance departure/spin resistance; and (4) the outlook for applications of these concepts to future fighters, particularly those designs which incorporate relaxed static stability
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