bluuebunny/crossref_metadata_2025_split huggingface dataset:
Experimental and Numerical Investigation of the Flow in a Vaneless Diffuser of a Centrifugal Compressor Stage. Part 1: Experimental Investigation
Authors: Sato T , Oh J M , Engeda A 
Published: November 2005

The flow in a radial vaneless diffuser downstream of a centrifugal compressor is highly complex, as the flow is turbulent, unsteady, viscous, and three-dimensional. Depending on the initial state of the end-wall boundary layers and the diffuser length, the flow may become fully developed or may separate from one of the walls. Therefore, to improve the diffuser performance, it is important to understand the flow field in the diffuser in detail. As the diffuser width is generally very small for most radial stages and an adverse pressure gradient exists, secondary flows are generated, making the flow fields more complicated. In addition, skewed boundary layers form on the wall surfaces. As flowrate is reduced, the flow field becomes more complicated and leads to rotating stall. This article presents detailed flow measurements in a vaneless diffuser of a centrifugal compressor stage with a very high flow coefficient radial impeller. Usually, centrifugal compressors with radial impellers are designed in the flow coefficient (ϕ) range ϕ = 0.01 - 0.16. Often, the need arises to design higher flow coefficient, ϕ, radial stages. Detailed measurements were carried out in the vaneless diffuser at seven radial positions downstream of a radial impeller designed for a very high flow coefficient of ϕ = 0.2. The experimental investigation was carried at four rotational speeds 13 000, 15 500, 18 000, and 20 500 r/min, but only the result of 20 500 r/min at near-design-point flowrate (5.11 kg/s) is reported in this article.
Experimental and Numerical Investigation of the Flow in a Vaneless Diffuser of a Centrifugal Compressor Stage. Part 2: Numerical Investigation
Authors: Sato T , Oh J M , Engeda A 
Published: November 2005

As user demands grew for improved performance and more reliable equipment and as compressor vendors sought improved analytical and design methodologies, the application of computational fluid dynamics (CFD) in the industrial world became a necessity. Fortunately, large increases in available, economic computing power together with development of improved computational methods now provide the industrial designer with much improved analytic capability. As CFD algorithms and software have continued to be developed and refined, it remains essential that validation studies be conducted in order to ensure that the results are both sufficiently accurate and can be obtained in a robust and predictable manner. Part I of this paper presented detailed flow measurements in a vaneless diffuser of a centrifugal compressor stage with a very high flow coefficient radial impeller, where measurements were carried out in the vaneless diffuser at seven radial positions downstream of the radial impeller designed for a very high flow coefficient of ϕ = 0.2. This paper, Part II, attempts to verify and validate the results numerically.
Some Guidelines on the Use of Profile Reliefs of High Contact Ratio Spur Gears
Authors: Yildirim N 
Published: November 2005

With reference to the previous articles of the author(s) based on the systematic approach to the profile relief design of both low contact ratio and high contact ratio spur gears, some guidelines are drawn for the use of short and double reliefs of the HCRG profile design under the effect of realistic parameters like variable tooth stiffness and manufacturing errors regarding the profile relief values. Root stress of the double relief can be minimized by optimizing the maximum tooth load value, hence the tooth load diagram with constant and variable tooth stiffness. Interaction of the manufacturing errors with the relief parameters is put into a form of analytical relation between manufacturing grades, hence the manufacturing tolerance and some gear parameters such as contact ratio, base pitch, and the load at which the smooth transmission error curve is required. In case of double relief, design load plays a major role in its selection. A relation and also a tabular form of guideline are given: for the required manufacturing grade if the contact ratio and other gear parameters are known and for the minimum contact ratio required if the manufacturing grade of the gears are known for either of the two cases short and double reliefs.
The effect of wake parameters on the transitional boundary layer on turbine blade
Authors: Zarzycki R , Elsner W 
Published: November 2005

This paper presents an experimental analysis of the interaction between wakes and boundary layers on an aerodynamic blade profile. The main objective of this research was to investigate the simultaneous influence of the freestream conditions and wake parameters on the wake-induced transition process. The investigations were performed for two levels of inlet freestream turbulence Tu = 0.4 and 3 per cent. The wakes were generated by cylindrical bars mounted in the rotating wheel. It was shown that wake parameters and especially the turbulence in the wake and wake width have a great influence on the position and extent of the induced transition. The role of freestream turbulence on the wake structure passing over the blade surface was also emphasized.
Effect of vane-rotor interaction on the unsteady flowfield downstream of a transonic high pressure turbine
Authors: Dénos R , Paniagua G 
Published: November 2005

This paper analyses the effect of the stator-rotor interference on the stage exit flow field of a transonic turbine operated under engine representative conditions in the von Karman Institute (VKI) compression tube facility. The test programme comprises three pressure ratios and two Reynolds numbers. The time-averaged radial distributions of total pressure and temperature downstream of the rotor are affected by the hub passage vortices and the interaction between the tip passage vortex and the rotor tip leakage vortex. The azimuthal distributions exhibit significant non-uniformities with a periodicity of one vane pitch. The amplitude of this non-uniformity is very sensitive to the pressure ratio. A simple model shows that, contrary to the common belief, the transport of the vane wake and secondary flows across the rotor is not enough to explain the magnitude of the variations. The pitch-wise vane exit static pressure distribution, which is significantly distorted owing to the transonic regime of the vane, should be taken into account. The amplitude of the time-resolved fluctuations of pressure and temperature, which are due to rotor blade passing events, also varies significantly depending on the probe location in a vane pitch. The measured time-accurate rotor relative inlet total pressure suggests that the rotor relative exit undergoes periodic excursions in the transonic regime.
Unsteady boundary layer studies on ultra-high-lift low-pressure turbine blades
Authors: Zhang X F , Hodson H P , Harvey N W 
Published: November 2005

The unsteady boundary layer development on the suction surface of two ultra-high-lift low-pressure (LP) turbine blades, known as T106C and U2, was investigated to further understand the loss reduction mechanism, which is integral to optimize the blade design in unsteady flow. The T106C profile is a mid-loaded ultra-high-lift LP turbine blade. Owing to the strong local adverse pressure gradient, the laminar boundary layer on the suction surface separates shortly after the suction side peak velocity. The turbulence within the incoming wakes cannot induce transition around the separation point because of the low receptivity of the laminar boundary layer. This allows the wake's negative jet to induce roll-up vortex, which reduces the benefits of the wake-induced transition. The wake-turbulence induced transition, which occurs downstream of the separation point, helps the separated boundary layer to reattach earlier. Owing to its mid-loaded nature, a large portion of the suction surface is covered by the reattached turbulent flow, which also contributes to the high profile loss. Therefore, LP turbine blades designed to make best use of unsteady flow effects should be aft-loaded. The ultra-high-lift blade U2 is an aft-loaded profile. Furthermore, the mild local adverse pressure gradient after the suction side peak velocity allows the laminar boundary layer to further develop before separation and results in a local Reθ of about 250 at separation. Therefore, the turbulence in the passing wake is able to induce transition close to the separation point. The earlier wake-induced transition and calmed region significantly reduce the size of the separation bubble. Furthermore, the earlier occurrence of wake-turbulence induced transition prevents the wake's negative jet from generating roll-up vortex, which also leads to lower losses.
Experimental investigations of rotating flow instabilities in the last stage of a low-pressure model steam turbine during windage
Authors: Gerschütz W , Casey M , Truckenmüller F 
Published: November 2005

Experimental investigations on two different three-stage low-pressure (LP) model turbines operated on steam during windage are presented. At very low flows, strain gauges identified that the two turbines exhibit different dynamic stress characteristics of the last-stage rotor blades. The first turbine experienced the highest vibrations from aerodynamic excitations at the resonant frequency of the second mode in a narrow operating range around 13 per cent of the design flow, whereas the second turbine experienced no resonance up to the fourth mode and has the highest dynamic loading at zero flow. Specially developed high-response total pressure probes have been used to determine the cause of the aerodynamic excitation from traverses of the unsteady pressure field at three planes in the last stage. The experimental data for both turbines show that unsteady pressure disturbances steadily grow when the flow is reduced below 25 per cent of design flow and that the excitations are strongest in the axial gap between the guide vane and the rotor of the last stage near the outer casing. Detailed analysis shows that high-amplitude disturbances occur at distinct frequencies and that these rotate in the circumferential direction at a fraction of the rotor speed. Comparison of the pressure signals measured at two circumferential locations on the casing of the second turbine confirmed the characteristic frequency pattern to be a so called ‘rotating instability’. This unsteady phenomenon arising from the tip leakage flow has previously been observed in axial flow fans and compressors and is demonstrated for the first time here in a turbine operating at very low flow rates.
Production routes of the alpha emitting 149Tb for medical application
Authors: Beyer G. J. , Čomor J. J. , Daković M. , Soloviev D. , Tamburella C. , Hagebø E. , Allan B. , Dmitriev S. N. , Zaitseva N. G. 
Published: November 2005

Summary
The partial alpha emitting lanthanide isotope 149Tb seems to have a great potential in systemic radioimmuno therapy (RIT), especially when single cells in transit or circulation are targeted. The isotope 149Tb has a half life of 4.118 h and decays by alpha emission (3.97 MeV, 17%) EC-process (76%) and β+-emission (7%). In this paper, we analyze the possible production routes: light- and heavy ion induced nuclear reactions and p-induced spallation.
The excitation functions for light- and heavy ion induced reactions have been calculated using the ALICE91 code. The direct nuclear reaction 152Gd (p, 4n) 149Tb was found to be the most promising production path. Alternatively, the indirect reaction 142Nd (12C, 5n) 149Dy → 149Tb seems to be much more suitable compared to the reaction on the mono-isotopic target element 141Pr 12C, 4n) 149Tb. In this case, both, the production yield of 149Tb and the radionuclidic purity are considerably lower, compared to the (p, 4n)-reaction. In preliminary experiments we produced 149Tb via the indirect reaction Nd (12C, 5n) 149Dy → 149Tb (108 MeV 12C+6 ions and 1 particle-µA) at the U-200 heavy ion cyclotron at the FLNR of the JINR Dubna. From a 1.25 h irradiation of a 12 mg/cm2
natNd2O3 target, we obtained 2.7 MBq of 149Tb (70 µCi) at 20 min EOB. This allows the conclusion, that a dedicated cyclotron equipped with a modern ECR-ion source, providing high ion currents would allow the continuous production of batches of the order of 10–20 GBq of 149Tb for routine RI-therapy.
The lower cross section of the spallation process can be compensated by using very thick targets. On-line mass separation technique provides high purity isotopically clean 149Tb preparations, independently on the production route chosen. At the ISOLDE facility at CERN, we prepared batches of up to 500 MBq 149Tb by combining on-line mass separation process followed by a cation exchange chromatography process using α-HIBA as eluent. The obtained 149Tb preparations showed excellent behavior in labeling of chelated monoclonal antibodies.
Selective dissolution of Am in basic media in the presence of ferricyanide ions: a mechanistic and structural study on Am(V) and Am(VI) compounds
Authors: Meyer D. , Fouchard S. , Simoni E. , DenAuwer C. 
Published: November 2005

Summary
Americium exhibits a soluble form in aqueous alkaline media in the presence of ferricyanide ions (Fe(CN)6
3−), which is not the case for the other transplutonium elements (TPE). This soluble Am compound can be obtained by addition of a concentrated basic solution of ferricyanide ions on a trivalent americium hydroxide precipitate. Thus, this technique enables a complete and rapid extraction of americium through its soluble form in alkaline solutions whereas under these conditions, other TPE and the lanthanides remain in the solid state as trivalent hydroxides. In the case of dissolution involving large amounts of americium, the formation of the soluble americium species is followed by the appearance of a reddish precipitate in the basic solution. Dissolution of the reddish solid in NaOH or NaOH/Fe(CN)6
3− media demonstrated the existence of a media-dependent solubility of the precipitate, and therefore the existence of at least two forms of soluble Am.
Spectroscopic (UV-visible, EXAFS-XANES, Raman) and electrochemical investigations were carried out on the different forms of americium to determine the nature of the compounds. This study points out that the reddish solid Am compound is probably a Am(V) hydroxide: Na2AmO2(OH)3·3H2O while the other Am species is a mixed americyl–ferricyanide complex. This work demonstrates that this dissolution of Am(III) solid compound is much more complex than a simple oxidation by the ferricyanide ions. The existence of a molecular interaction between Am(V)O2
+ and ferricyanide ions is highly probable. This selective dissolution of americium by a basic ferricyanide solution can be used to define a separation process of Am from lanthanides and other transplutonium elements in the field of high level liquid waste treatment.
The kinetics and mechanism of the reduction of neptunium (VI) ions by uranium (IV) ions in nitric acid
Authors: Koltunov V. S. , Taylor Robin J. , Marchenko V. I. , Zhuravleva G.I. , Mezhov E.A. , Koltunov G. V. , Dvoeglazov K. N. 
Published: November 2005

SummaryThe rapid reduction of NpO22+ions to NpO2+by U(IV) ions in an aqueous nitric acid solution has been studied and, in many ways, is similar in character to the same reaction in HClO4. The major difference is that in HNO3the reaction proceedsviatwo parallel routes. The first isviathe hydrolysed UOH3+ion, as in the reaction in HClO4and the second isviathe non-hydrolysed U4+ion. These parallel routes lead to the observed order of reaction with respect to H+ions being reduced from −1 in HClO4to −0.7 in HNO3. After accounting for the reaction mechanism the rate equation is described by:wherek8= 404 min−1,k19= 275 M−1min−1and β = 0.009 M at 10 °C and μ = 2. The activation energy was 66.5 ± 4.9 kJ mol−1. Nitrate ions had no effect on the reaction rate but sulphamic acid increased the observed rate, probably through catalysis by sulphate ions arising from sulphamic acid reaction with HNO2and hydrolysis.
Determination of237Np at trace level: evaluation of various analytical procedures
Authors: Baglan Nicolas , Bouvier-Capely C. , Cossonnet C. 
Published: November 2005

Summary237Np is a long-lived actinide (2.14 × 106y), an α emitter, which is present either in the fuel cycle or in the environment as a result of local fallout. Due to the low concentration level encountered in bioassays or environmental samples, a preconcentration is necessary and several analytical tools can be used, namely: α-spectrometry, PERALS (Photon Electron Rejecting Alpha Liquid Scintillation) or ICP-MS (Inductively Coupled Plasma-Mass Spectrometry).In the case of actinide mixtures where interference can occur, a radiochemical separation is necessary prior to measurement in order to obtain a pure fraction of each actinide. In this paper different approaches, still in use for actinide mixtures and based on ion exchange, extraction chromatography and solvent extraction, are investigated and compared for237Np analysis on synthetic solutions.In addition, the suitability of the various procedures is discussed for Np regarding several criteria such as the constraints of the analytical tool, the concentration level, the time needed for the analysis and waste generation.
Preparation of U(VI) and Th(IV) α-sources from calcium nitrate solutions by combining solvent extraction and electrodeposition procedures
Authors: Elyahyaoui A. , Zarki R. , Chiadli A. 
Published: November 2005

Summary
A simple method of preparing α-sources for alpha spectrometric analysis of uranium and thorium is investigated by combining solvent extraction and electrodeposition procedures. Extraction of these actinides is performed by diethyl ether from calcium nitrate solution with various nitric acid concentrations. Recoveries of 90–100% are obtained for uranium and 83.5% for thorium. Good resolutions are also achieved under optimum conditions.
The dependence of the overall yield of U(VI) and Th(IV) is examined in relation to the aqueous phase acidity. A procedure combining solvent extraction and electrodeposition is proposed for a selective α-source preparation of U(VI) and Th(IV). Uranium is first extracted at pH range about 1 to 2. At this acidity, thorium remains in the aqueous phase and may be subsequently extracted from this after acidification with 2 M HNO3. A second decontamination of a specific nuclide is achieved by a selective electrodeposition using electrolyte consisting of about 70% ethanol, 0.45 M hydrochloric acid, 0.09 M acetic acid and 108 µg Fe2O3, with concentrations above 0.48 M in HCl for U(VI) or 0.06 to 0.09 M in HNO3 for Th(IV).
Complexation and luminescence spectroscopic studies of europium(III) with polymaleic acid
Authors: Montavon G. , Markai S. , Billard I. , Nehlig A. , Grambow Bernd 
Published: November 2005

Summary
The complexation behavior of europium(III) with polymaleic acid (PMA) was studied at pH 5 in 0.1 M NaClO4 by anion exchange (AE). The concentration range investigated was from E-9 M to E-4 M for the europium ion and from 1 to 50 mg/l for the polymer. The quantitative description of experimental data showed the formation of a 1 : 1 Eu : PMA complex and the existence of at least two distinct interaction environments ("sites") of Eu with the polymer chain whose proportions varied with the ratio between total Eu and PMA concentrations. The existence of different sites was further demonstrated by Time Resolved Laser-induced Fluorescence Spectroscopy (TRLFS) measuring the lifetimes and emission spectra of EuPMA complexes. By using empirical relationships, environments implying 1 : 2 and 1 : 1 Eu : COO− coordination could be deduced. The results show similarities with published data obtained for fulvic and Aldrich humic acids as far as complexation properties at pH = 5 are concerned.
Multitracer study on the uptake mechanism of yttrium and rare earth elements by autumn fern
Authors: Ozaki Takuo , Ambe Shizuko , Enomoto S. , Minai Y. , Yoshida S. , Makide Y. 
Published: November 2005

Summary
Irrespective of low bioavailability, some plant species accumulate Y and rare earth elements (REEs) to a great extent (accumulator species). The uptake mechanisms of Y and REEs were investigated for autumn fern, one of accumulator species. For comparison, plant species which accumulated poorly REEs (non-accumulator species) were also studied. In the present investigation, two noticeable phenomena were observed. (I) Autumn fern showed no ionic-radius dependence of Y-REE uptake by leaves, while non-accumulator species showed an extremely high uptake for Y compared with REEs. (II) Y-REE uptake by autumn fern was influenced by the addition of chelating reagents to the uptake solution, while no effect was observed for non-accumulator species.
Photosensitized Oxidation and Inactivation of Pyocyanin, a Virulence Factor of Pseudomonas aeruginosa
Authors: Reszka Krzysztof J. , Denning Gerene M. , Britigan Bradley E. 
Published: November 2005

ABSTRACTPyocyanin (PyO−) (1‐hydroxy‐5‐methylphenazine) is a cyto‐toxic compound secreted by Pseudomonas aeruginosa, an omnipresent bacterium and a human pathogen. We report that visible light illumination in the presence of rose bengal, or riboflavin, in aerated solutions (pH 7.0‐7.2) induces irreversible loss of the pigment's characteristic absorption band at 690 nm, indicating its oxidation. This photobleaching was paralleled by generation of a multiline Electron Paramagnetic Resonance (EPR) spectrum attributed to a PyO−‐derived radical. The reaction was dependent on the presence of air, sensitizers and light, was inhibited by sodium azide and was unaffected by ethanol. This suggests that PyO− was oxidized largely via singlet oxygen and that hydroxyl radicals were not involved. The photochemically modified pigment was less efficient in oxidizing NAD(P)H and generated less superoxide (by ∼50%) than the intact PyO−, indicating its partial inactivation. l‐Methoxy‐5‐methylphenazine, a PyO− analog in which the ‐O− moiety was replaced by the methoxy group (‐OMe), was resistant to oxidation, suggesting that oxidation of PyO− involves its phenolate moiety. These results also suggest that photosensitization could be a potentially useful method for inactivation of PyO− and, possibly, detoxification of superficial wounds (skin, eye) infected with P. aeruginosa.
Inside Front Cover: Selective Construction of Supramolecular Nanotube Hosts with Cationic Inner Surfaces (Adv. Mater. 22/2005)
Authors: Kameta N. , Masuda M. , Minamikawa H. , Goutev N. V. , Rim J. A. , Jung J. H. , Shimizu T. 
Published: November 2005

AbstractSelective construction of a supramolecular nanotube host with a cationic inner surface consisting of unsymmetrical bolaamphiphiles is reported on p. 2732 by Masuda, Shimizu, and co‐workers. The nanotube, shown schematically on the inside cover, has different inner and outer surfaces covered with amino and sugar functionalities, respectively, and is able to effectively encapsulate anionic nanomaterials, such as sulfate‐latex beads (see TEM image) and spherical proteins, in the cationic hollow cylinder without depending on capillary action.