bluuebunny/crossref_metadata_2025_split huggingface dataset:
Magnetization transfer based contrast for imaging denatured collagen
Authors: Harel Amir , Eliav Uzi , Akselrod Solange , Navon Gil 
Published: April 2008

AbstractPurposeTo study of the sensitivity of various NMR and MRI methods and parameters to the degree of thermal denaturation of collagen.Materials and MethodsCollagen type I powder was washed with methanol:chloroform to remove traces of lipids and then suspended in saline. Denaturation was carried out by heating the suspension for 5–120 minutes at a temperature range of 50–100°C. The NMR methods tested were two T2 filter methods: Goldman‐Shen (GS) and Edzes‐Samulski (ES); magnetization transfer contrast (MTC); double quantum filtering (DQF) and high resolution spectroscopy. MRI contrasts based on these methods were compared.ResultsThe following parameters were found to be sensitive to denaturation of collagen: 1) the amount of spins that experience high dipolar interactions as assessed by DQF; 2) MTR; 3) kwT1w (where kw is the magnetization transfer rate from water to collagen, and T1w is the water protons longitudinal relaxation time); and 4) aliphatic residues content. The contrast between native and denatured collagen was improved by all the tested methods, with ES and DQF producing the highest contrast.ConclusionMethods depending on T2 filtering and DQF were found to be sensitive to the degree of thermal denaturation of collagen and improve the contrast between native and denatured collagen. J. Magn. Reson. Imaging 2008;27:1155–1163. © 2008 Wiley‐Liss, Inc.
Correction for heart rate variability during 3D whole heart MR coronary angiography
Authors: Roes Stijntje D. , Korosoglou Grigorios , Schär Michael , Westenberg Jos J. , van Osch Matthias J.P. , de Roos Albert , Stuber Matthias 
Published: April 2008

AbstractPurposeTo evaluate the effect of a real‐time adaptive trigger delay on image quality to correct for heart rate variability in 3D whole‐heart coronary MR angiography (MRA).Materials and MethodsTwelve healthy adults underwent 3D whole‐heart coronary MRA with and without the use of an adaptive trigger delay. The moment of minimal coronary artery motion was visually determined on a high temporal resolution MRI. Throughout the scan performed without adaptive trigger delay, trigger delay was kept constant, whereas during the scan performed with adaptive trigger delay, trigger delay was continuously updated after each RR‐interval using physiological modeling. Signal‐to‐noise, contrast‐to‐noise, vessel length, vessel sharpness, and subjective image quality were compared in a blinded manner.ResultsVessel sharpness improved significantly for the middle segment of the right coronary artery (RCA) with the use of the adaptive trigger delay (52.3 ± 7.1% versus 48.9 ± 7.9%, P = 0.026). Subjective image quality was significantly better in the middle segments of the RCA and left anterior descending artery (LAD) when the scan was performed with adaptive trigger delay compared to constant trigger delay.ConclusionOur results demonstrate that the use of an adaptive trigger delay to correct for heart rate variability improves image quality mainly in the middle segments of the RCA and LAD. J. Magn. Reson. Imaging 2008;27:1046–1053. © 2008 Wiley‐Liss, Inc.
Vibrational transitions in Rydberg matter clusters from stimulated Raman and Rabi‐flopping phase delay in the infrared
Authors: Holmlid Leif 
Published: April 2008

AbstractRecently, rotational spectra of giant Rydberg matter (RM) clusters were studied in the radio frequency range (Mol. Phys. 105 (2007) 933–939), giving high‐precision bond distances in the nanometer range. However, the theoretical and experimental problem of vibrational motion or, rather, coupled electronic‐vibrational motion in the RM clusters is still unsolved; but it is expected that broad phonon bands will exist. Spectroscopic signatures from space make it likely that RM is a common form of matter in the Universe, and phonon bands in this spectroscopic range have not been taken into account so far. Spectroscopic results are now reported on transitions in the range 0.01–20 cm−1, using primarily infrared (IR) lasers to probe the RM in a tunable open cavity with a Fabry–Perot interferometer to aid in the identification of the shifts. Stimulated Raman scattering from electronic transitions and Rabi‐flopping from electronic states in the clusters are observed. The broad stimulated Raman peaks are assigned to one and two consecutive vibrational (electronic‐vibrational) transitions. Theoretical values predicted for vibrations (phonon maxima) and electronic processes are in reasonable agreement with the experimental results. Improved calculations are needed to verify the assignments of the vibrational phonon distributions. Copyright © 2008 John Wiley & Sons, Ltd.
Bridging boundaries: Meeting the challenge of workplace diversity
Authors: Ernst Christopher , Yip Jeffrey 
Published: April 2008

AbstractIn today's globally diverse and increasingly interconnected world, social identity boundaries rub together, pull apart, and collide in the workplace. When identity divides open up, people look to leaders to bridge the gaps. By employing four tactics—suspending, reframing, nesting, and weaving—leaders can facilitate positive cross‐boundary interactions.
Novel Types of Carborane‐Carrier Hyaluronan Derivatives via “Click Chemistry”
Authors: Di Meo Chiara , Panza Luigi , Campo Federica , Capitani Donatella , Mannina Luisa , Banzato Alessandra , Rondina Maria , Rosato Antonio , Crescenzi Vittorio 
Published: April 2008

AbstractTwo new HA derivatives bearing carborane rings were synthesized by click chemistry. The optimal conditions were assessed for the preparation of biocompatible boron carriers, potentially suitable for application in BNCT and capable of targeting the CD44 antigen. The new polymeric samples were characterized by means of NMR‐spectroscopy techniques that gave degrees of 17 and 8% for HAAACB and HapACB, respectively. Both HAAACB and HApACB turned out to be nontoxic for colorectal, ovarian and bladder tumor cell lines, to disclose a specific interaction with the CD44 antigen as the native hyaluronan moiety, and to deliver boron‐atom concentrations largely sufficient for BNCT therapy when accumulated in cancer cells.magnified image
Poly(esterimide) Wire Enamels: Coatings with the Right Combination of Thermal and Mechanical Properties for Many Applications
Authors: Biondi Giovanna 
Published: April 2008

AbstractElectrical insulating enamels are usually made of thermosetting resins diluted in suitable solvents, which can be enameled on magnetic wires. PEI‐based enamel is one of the most important insulating enamels in electrical engineering. The characteristics of various PEI based wires are quite different depending on the final use. Using special additives, it is possible to produce optimized PEI versions with improved characteristics. Special applications are possible by introducing pigments or conductive materials in the formulation. Thermoplastic PEI are also obtainable. This review gives an overview of the fascinating world of PEI, from discovery up to the latest developments.magnified image
Synthesis and Performance of PP Microfiltration Membranes Grafted with Polymer Layers of Different Structure
Authors: Yang Hu , Ulbricht Mathias 
Published: April 2008

AbstractReproducible and controllable hydrophilic layers were grafted on macroporous PP membranes by surface initiated grafting. Two methods were adopted, i.e., through adsorption of or entrapping the photo‐initiator on the membrane surface. The latter method yielded longer grafted chains under otherwise identical conditions. Depending on monomer solution composition, brush layers or network‐like structures were grafted onto the entire membrane surface without significant loss of water flux. The influence of the structure of grafted layers on water permeation, protein adsorption, and protein microfiltration fluxes was investigated. It was found that membranes grafted with network‐like structures have the best performance.magnified image
Melt Elongation of Polymer Nanocomposites: A Method for the Controlled Production of Dichroic Films
Authors: Schmid Daniel , Handge Ulrich A. , Gann John P. , Yan Mingdi , Caseri Walter 
Published: April 2008

AbstractA processing method based on stretching of molten polymer nanocomposites was applied to prepare dichroic films. First, dodecanethiol‐capped gold particles were embedded in low density polyethylene. The resulting isotropic films were stretched in the melt under uniaxial loading using an elongational rheometer. The melt elongation technique resulted in reproducible characteristics of the optical properties and can be directly transferred to an industrial scale. The organic coating of the metal particles plays an important role in the generation of the dichroism. A reactive surface (adsorbed perfluorophenyl azide) led to strongly agglomerated particles which obviously did not lead to dichroic films.magnified image
UV‐Cured Interpenetrating Acrylic‐Epoxy Polymer Networks: Preparation and Characterization
Authors: Sangermano Marco , Carbonaro William , Malucelli Giulio , Priola Aldo 
Published: April 2008

AbstractAcrylic‐epoxy interpenetrating polymer networks were prepared by means of UV curing. The photopolymerization process was investigated via real‐time FTIR spectroscopy. The hybrid, cured films showed a broad tan δ peak in DMTA demonstrating the high damping properties of the hybrid, cured formulations. A decrease on shrinkage was achieved by increasing the epoxy‐resin content in the photocurable formulation, with a consequent increase in adhesion properties.magnified image
The Silane‐ene and Silane‐Acrylate Polymerization Process: A New Promising Chemistry?
Authors: El‐Roz Mohamad , Lalevée Jacques , Allonas Xavier , Fouassier Jean‐Pierre 
Published: April 2008

AbstractThe combination of silanes and enes yields highly reactive photopolymerizable mixtures that exhibit very low oxygen sensitivity. Diphenylsilane (SiH) has been used in combination with different multifunctional acrylates (AC) and conversions of 100% and about 25% for AC and SiH, respectively, have been reached. Final tack free polymers are obtained as a consequence of the fact that the polymerization rates are not affected by oxygen. When using vinylacetate (VA), divinylether (DVE), and allylether (AE) units, the final silane conversion still remains low (50, 20, and 20%, respectively) but are promising. The reactivity of the silyl radicals is investigated by laser flash photolysis. The role of the bond dissociation energy of the silane is outlined.magnified image
Large plastic stability in magnesium alloys: crystalline vs. amorphous alloys
Authors: Boissière R. , Puech S. , Blandin J.J. 
Published: April 2008

AbstractExcept if strain induces damage, the plastic stability can be roughly estimated thanks to the value of the strain rate sensitivity parameter m. In conventional magnesium alloys, moderate values of m (typically close to 0.3) can be frequently obtained during high temperature deformation. Such values allow reaching significant elongations to fracture. For alloys displaying fine grains, superplastic properties associated with values of m of about 0.5 or more are achievable leading to large elongations to fracture in optimized conditions for which damage processes remain limited. Quite recently, amorphous magnesium alloys have been produced in bulk conditions. In appropriate conditions of deformation, these alloys display Newtonian behaviour (i.e. m = 1). With such rheologies, the plastic stability is expected to be maximal. In this presentation, features in relation with high temperature deformation of amorphous and crystalline magnesium alloys will be compared and apparent similitudes and differences will be discussed.
High resolution surface studies of superplastic deformation in shear and tension
Authors: Rust M.A. , Todd R.I. 
Published: April 2008

AbstractDespite decades of study, the fundamental mechanisms of superplasticity, particularly relating to the accommodation of grain boundary sliding, are still widely disputed. This is partly due to a lack of information on individual grain deformation and sliding events. Previous studies of superplasticity using surface markers have tended to use either diamond paste scratches, which make quantitative measurements difficult and are open to widely varying interpretation, or regular grids with spacing greater than the grain size, which prevents measurements of intragranular deformation. Recent work has shown that a Focussed Ion Beam (FIB) can be used to create regular, repeating grid marker systems with pitches varying from 0.25 to more than 50 microns. Previously published results in Sn‐Pb have shown the power of this technique, particularly regarding the lack of intragranular deformation and surface grain boundary sliding accommodation mechanisms. The current study has applied the FIB technique to Al5083, a pseudo‐single phase alloy. Tensile tests have been performed with elongations from 5 % to 150 %. Additionally, analogous biaxial shear tests have been performed for comparison and to limit the free surface effects. SEM images of FIB markers before and after deformation have been acquired, and quantitative measurements of the localized strains have been made using 3‐D tilt reconstruction. Shear and tension results show several distinct features. However, no significant intragranular deformation is seen under either set of strain conditions. Possible accommodation mechanisms are discussed.
Titan 6–4 hemispheres for SCA system of ariane 5
Authors: Beck W. , Duong L. , Rogall H. 
Published: April 2008

AbstractFunded by the European Space Agency (ESA), the Ariane 5 Program has been developed under the responsibility of the CNES, the French Space Agency. Attitude Control of the Ariane 5 Mission is carried out by the SCA (Systeme Controle d'Attitude), developed by Astrium‐Space Transportation (Astrium‐ST). It is the blow down hydrazine system using gaseous nitrogen as pressurant. The ARIANE 5 ‐SCA Tank ‐ Fig.1 ‐ is manufactured from TiAl6V4‐hemispheres essentially performed via Super Plastic Forming (SPF) process. The tank shell wall thickness achieved need not to be mechanically reworked except small domains prepared for welding. Vis‐à‐vis the common tank production which employs hemispheres resulted by mechanical milling out of forged shell, the SPF provides certainly saving on milling efforts as well as significant reduction on material wasting. Also shown that is for tank component submitted to space application, the SPF as production method commonly undergoes development and verification efforts in engineering elaborating focused on Test‐shell, Qualification‐shell and such which provides samples for material strength and technological verifications. Enclosing is also a brief overall display addressing successful use of SPF‐shell in producing tanks for the space flight today. Up to now more then 100 Tanks have been manufactured by Astrium‐ST and > 90 Tanks were successful used in Ariane 5 launchers with various missions.
Design, production and testing of a titanium exhaust duct for noise and weight reduction
Authors: Beck W. , Chaniot D. , Larrouy T. , Marcel Y. , Yannovitch P. 
Published: April 2008

AbstractHelicopter exhausts are usually basic components not yet developed to achieve the best noise reduction performance. This needs to change to continue complying with ever more restrictive noise regulations. A more efficient acoustic design could be reached using a complex configuration with assembly of multiple walls and 3D optimized geometry. As the exhausts nozzle are usually built out of Ni based alloys, the weight of such a component would increase. Such an increase could have a negative effect on the payload of the aircraft. Due to high temperatures and pressures of gas stream, Cp Titanium is limited for this application but heat resistant titanium alloys such as Beta21S and Ti 6–2‐4–2 would be a good substitution material as it provides significant weight reduction and capacity to sustain further power increase of the Helicopter engines. An European Project named “HORTIA” was funded to demonstrate the feasibility of using Heat and Oxidation Resistant Titanium Alloys for exhaust ducts in a noise and weight reduction objective. Studies were conducted on these materials to evaluate their mechanical performances and resistance against corrosion at high temperature for a service application. A thermo‐mechanical simulation of stress and temperature fields validated the definition design of a new component in an acoustically efficient configuration. An analysis of forming and welding parameters led to the industrial manufacturing of a complete exhaust with techniques like Super‐Plastic Forming and Laser Beam Welding. Finally the nozzle was successfully tested on en engine test bed for endurance and acoustic performance.
Finite element based predictions of life limiting behaviour for a large SPF tool
Authors: Deshpande A.A. , Leen S.B. , Hyde T.H. 
Published: April 2008

AbstractSPF tool distortion due to the thermal cycling can lead to the forming of faulty SPF parts. In addition, thermo‐mechanical fatigue and creep can cause cracking, which eventually lead to un‐repairable damage to the tool. The aim of this paper is to investigate the thermo‐mechanical distortion behaviour of a representative large SPF tool under realistic forming conditions using finite element analysis. Platen‐tool contact and clamping pressure along the edges of the tool during the dwell time are modelled. The effects of heating and cooling cycles on tool distortion are analysed using different thermal histories with different heating and cooling rates. The effect of batch size on tool distortion is evaluated to optimise the batch size.
Increasing stable deformation by declining temperature during the process
Authors: Ziegelheim J. , Ohsawa H. , Motegi H. , Koiwai K. 
Published: April 2008

AbstractRecently increasing amount of light metal sheets, especially based on magnesium, is being involved into various structural constructions and functional components. Such a rising trend can be observed, for instance, at automotive, aerospace and electronic industry. On the other hand there exist some processing difficulties, such as forming limits, caused by crystalline structure.To make processing of magnesium materials most reasonable with a maximum economical and material’s effect, detailed investigation of the material’s mechanical behavior is necessary to realize. Especially, an use of superplasticity is a point of the main interest. By optimum settings of the deformation process (especially temperature and strain rate) the superplastic conditions were determined optimally. Moreover, it was discovered that variable temperature very positively affects the superplasticity of magnesium materials. Actually by changing temperature conditions during the deformation, even higher level of superplastic deformation without rupture can be obtained. This very interesting fact was observed at the elevated temperatures that decrease almost constantly during the deformation process.Thus previously widely used constant temperature treatment opens door to the dynamic problems of searching for the optimal temperature gradient and its variation.
The manufacture of superplastic Magnesium alloy sheet
Authors: Grimes R. , Jackson M. , Moorhouse B. , Dashwood R. 
Published: April 2008

AbstractProbably because of their propensity to dynamically recrystallise, superplastic behaviour can be obtained from magnesium alloys considerably more easily than from comparable aluminium alloys. In some cases even as cast magnesium alloys can exhibit reasonable superplasticity and there appears no need for the special alloying additions or complex thermal mechanical treatments required by aluminium alloys such as AA2004 or AA7475. The paper describes the superplastic behaviour (in uniaxial tension) and microstructure of sheet processed from strip cast AZ31 and AZ91. The material was tested in the as‐cast condition and after warm rolling to a number of gauges. Industrially useful superplastic capability was demonstrated in strip cast AZ31 and AZ91 in the as cast condition. Furthermore good superplastic capability was also demonstrated in sheet rolled from the cast metal and the ductilities obtained were not significantly influenced by rolling strain. Twin roll strip casting represents a feasible and simple route for the production of superplastic material either for use in the as cast condition or after rolling to the required gauge.
Superplastic forming of friction stir welds in Titanium alloy 6Al‐4V: preliminary results
Authors: Sanders D.G. , Ramulu M. , Edwards P.D. 
Published: April 2008

AbstractThe trend in design and fabrication of aerospace structure is moving rapidly towards the use of composite materials and the consolidation of many pieces into large monolithic assemblies. Titanium alloy 6Al‐4V is more compatible with composite materials than aluminum alloys because of its superior corrosion resistance and closer match to the coefficient of thermal expansion. In addition, many components that are used for the newer composite based aircraft, and are subjected to high service temperatures, are fabricated from titanium using Superplastic Forming (SPF) and Diffusion Bonding (SPF/DB). However, the use of SPF titanium parts has been limited up until now due the size restriction of standard sheets from the titanium mills, which is generally available at a maximum size of 1.2 m x 3.6 m. The purpose of this study was to develop the Friction Stir Welding (FSW) process for both standard and fine grain titanium alloy 6Al‐4V in a bid to find a process that would allow the joining of multiple pieces to fabricate much larger components. Further, the FSW process was refined such that the welds were made to have superplastic properties equal to those of the parent sheet. A secondary goal of this effort was to build full size SPF prototype parts of a generic jet engine nacelle Lipskin using one FSW titanium blank. SPF of 7475 aluminum had been reported previously in the literature by Mahoney, Barnes, Mishra and others. During this study, the FSW process for 5083 Superplastic grade aluminum was developed simultaneously along with titanium 6Al‐4V. The aluminum material was used to reduce the cost of developing the SPF manufacturing process to fabricate full scale engine inlet test components. FSW blanks of both materials were used for the initial forming trials.
Enhanced superplastic deformation behavior of ultrafine‐grained Ti‐6Al‐4V alloy
Authors: Saitova L. , Semenova I. , Höppel H.W. , Valiev R. , Göken M. 
Published: April 2008

AbstractThe mechanical behavior of the Ti‐6Al‐4V ELI alloy in both conventional grain size (CG) and ultrafine‐grained (UFG) conditions under tension and compression at elevated temperatures (500–800 °C) is considered. Grain refinement by equal‐channel angular pressing (ECAP) followed by multicycle extrusion was observed to result in a considerable improvement of superplastic characteristics of Ti‐6Al‐4V ELI alloy. The alloy exhibits a superplastic deformation behavior already at 600 °C. The enhanced regime of superplasticity allows more efficient forming of parts and components. In addition, the UFG microstructure and, consequently, enhanced mechanical properties are kept after superplastic forming.