bluuebunny/crossref_metadata_2025_split huggingface dataset:
Constitution and Mechanical Properties of Nanocrystalline Reactive Magnetron Sputtered V‐Al‐C‐N hard Coatings as a Function of the Carbon Content
Authors: Ziebert Carlos , Albers Ulrich , Stüber Michael , Ulrich Sven 
Published: May 2009

AbstractNanocrystalline V‐Al‐C‐N hard coatings were deposited without substrate bias by reactive r.f. magnetron sputtering from a segmented target, composed of ceramic VC and AlN pieces, following a combinatorial materials science approach. In each experiment, six coatings of different compositions and microstructures were obtained simultaneously by placing six substrates in individual positions relative to the target. The Ar gas flow was kept constant while the CH4 gas flow was systematically varied from 0 to 5 sccm corresponding to CH4 contents of 0–8% of total Ar + CH4 flow in order to study the formation of nanocrystalline, metastable and nanocomposite phases and the influence of the carbon content on the coatings constitution and mechanical properties by EMPA, XRD, nanoindentation and ball‐on‐disk tribometer tests.
Contact Fatigue Behavior of PVD‐Coated Steel
Authors: Ramírez Giselle , Tarrés Elena , Casas Begoña , Valls Isaac , Martínez Rosario , Llanes Luis 
Published: May 2009

AbstractIn this study, the contact fatigue behavior of a PVD TiN coating deposited onto DIN 1.2379 cold‐work tool steel is assessed by cyclic spherical indentation. Experimental characterization focuses on the evaluation of critical contact pressures, under both monotonic and cyclic loading, affiliated to the emergence of distinct damage events: circumferential cracking and cohesive spallation at the film or decohesion at the substrate–coating interface. Experimental findings indicate that the coated tool steel studied is susceptible to mechanical degradation under fluctuating contact loads, and the corresponding effective fatigue sensitivity varies depending on the mechanism recalled for defining critical damage.
An Analysis of Residual Stresses in Thermal Barrier Coatings: A FE Performance Assessment
Authors: Taymaz Imdat 
Published: May 2009

AbstractInternal combustion engines have been widely used for past 100 years. In the development of engine components a number of special techniques are used to compact the hostile operating environment, which usually includes high and cyclic forces, high and cyclic temperatures, sliding and often corrosion and/or erosion. In this study, 3‐D finite element structural and thermal analyses were carried out on both uncoated (without coating) and ceramic‐coated engine piston. A 150 µm super alloy bond coating (NiCrAlY) was first applied to the piston. Then, piston was covered by 350 µm thickness of MgZrO3 as top coating. The analysis can be utilized to detect possible thermal problem spots in an engine, and to provide input data for general engine modeling and engine lubrication and wear studies.
Native like structure in the unfolded state of the villin headpiece helical subdomain, an ultrafast folding protein
Authors: Meng Wenli , Shan Bing , Tang Yuefeng , Raleigh Daniel P. 
Published: May 2009

AbstractThe villin headpiece subdomain, HP36, is the smallest naturally occurring protein that folds cooperatively. Its small size, rapid folding, and simple three‐helix topology have made it an extremely popular system for computational studies of protein folding. The role of unfolded state structure in rapid folding is an area of active investigation, but relatively little is known about the properties of unfolded states under native conditions. A peptide fragment, HP21, which contains the first and second helices of HP36 has been shown to be a good model for structure in the unfolded state of the intact domain but a detailed description of the conformational propensities of HP21 is lacking and the balance between native and nonnative interactions is not known. A series of three‐dimensional NMR experiments were performed on 13C, 15N‐labeled HP21 to investigate in detail its conformational propensities. Analysis of 13Cα, 13Cβ, 13CO chemical shifts, Δδ13Cα − Δδ13Cβ secondary shifts, the secondary structure propensity scores, NOEs, 15N R2 values and comparison of experimental chemical shifts with those of HP36 and with chemical shifts calculated using the SHIFTS and SHIFTX programs all indicate that there is significant native like structure in the HP21 ensemble, and thus by implication in the unfolded state of HP36.
Interacting membranes
Authors: Berman D. , Thompson D.C. 
Published: May 2009

AbstractIn these proceedings we survey recent advances in M‐theory. After a brief review of the foundations of M‐theory we look at how the extended objects, namely M2 and M5 branes, interact with each other. We then describe the new proposals for the low energy dynamics of multiple coincident M2 branes including the theories of Bagger‐Lambert (BL) and Aharony‐Bergman‐Jafferis‐Maldacena (ABJM) and generalisations thereof. We finish with a presentation of some emerging conclusions and a discussion of unresolved puzzles.
Beyond the Twilight Zone: Automated prediction of structural properties of proteins by recursive neural networks and remote homology information
Authors: Mooney Catherine , Pollastri Gianluca 
Published: May 2009

AbstractThe prediction of 1D structural properties of proteins is an important step toward the prediction of protein structure and function, not only in the ab initio case but also when homology information to known structures is available. Despite this the vast majority of 1D predictors do not incorporate homology information into the prediction process. We develop a novel structural alignment method, SAMD, which we use to build alignments of putative remote homologues that we compress into templates of structural frequency profiles. We use these templates as additional input to ensembles of recursive neural networks, which we specialise for the prediction of query sequences that show only remote homology to any Protein Data Bank structure. We predict four 1D structural properties – secondary structure, relative solvent accessibility, backbone structural motifs, and contact density. Secondary structure prediction accuracy, tested by five‐fold cross‐validation on a large set of proteins allowing less than 25% sequence identity between training and test set and query sequences and templates, exceeds 82%, outperforming its ab initio counterpart, other state‐of‐the‐art secondary structure predictors (Jpred 3 and PSIPRED) and two other systems based on PSI‐BLAST and COMPASS templates. We show that structural information from homologues improves prediction accuracy well beyond the Twilight Zone of sequence similarity, even below 5% sequence identity, for all four structural properties. Significant improvement over the extraction of structural information directly from PDB templates suggests that the combination of sequence and template information is more informative than templates alone. Proteins 2009. © 2009 Wiley‐Liss, Inc.
The Cheshire Cat on engineering design
Authors: Hazelrigg George A. 
Published: May 2009

AbstractIn Lewis Carroll's Alice in Wonderland, the Cheshire Cat provides to Alice the underlying tenets of modern normative decision theory. These tenets are clear and simple. Yet few engineers have grasped their significance, and many design methods in common practice violate them with potentially devastating consequences. This paper reviews the advice given to Alice by the Cheshire Cat and places it in the context of engineering design. It goes on to discuss the contributions of von Neumann and Morgenstern as they add to the Cat's advice. Published in 2009 by John Wiley & Sons, Ltd.
Electronic structure calculations of carbon nanohorns for their chemical state analysis using soft X‐ray spectroscopy
Authors: Amano Taiji , Muramatsu Yasuji 
Published: May 2009

AbstractThe electronic structure of carbon nanohorns (CNHs) was calculated by the discrete variational ‐Xα molecular orbital method to analyze the electronic structure and/or chemical state using soft X‐ray spectroscopy. Five isomers of CNH, C115H25, C158H26, C135H21, C102H16, and C118H16, were successfully modeled. Slight differences in the electronic structure between the hexagonal and pentagonal rings of the CNH models can be understood from the orbital population, net charge, and bond overlap population. The calculated density of states in the C2p orbitals can be used for spectral analysis of soft X‐ray emission and absorption in the CK region of CNH. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2008
DV‐Xα study on the electronic structure of C120 isomers derived from the general Stone–Wales rearrangement
Authors: Takashima Akito , Nishii Toshiaki , Onoe Jun 
Published: May 2009

AbstractThe electronic properties, in particular the role of 7‐ and 8‐membered rings in the highest occupied molecular orbital (HOMO)–lowest unoccupied molecular orbital (LUMO) gap, of stable C120 isomers derived from the general Stone‐Wales rearrangement have been investigated using the discrete‐variational Xα MO method. It is found that the adjacent 7‐membered rings located in the waist region of the isomers tend to have positive effective charges, and that the electron polarization induced by the adjacent 7‐membered rings makes the HOMO level higher, which reduces the HOMO–LUMO gap of the C120 isomers. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2009
Fluorescence spectra of Pr3+ ions in phosphate materials calculated by the DVME method
Authors: Kowada Y. , Noma S. , Ogasawara K. 
Published: May 2009

AbstractRecently, fluorescence spectra of rare‐earth ions in oxide materials are very attractive for the applications of the optical amplification in optical fiber communications, white LED, etc. However, it has been difficult to calculate the fluorescence spectra of rare‐earth ions by the first principle method. In this study, we used the relativistic discrete‐variational multielectron (DVME) method, which is a configuration‐interaction (CI) calculation program using the molecular orbitals obtained by the relativistic DV‐Xα method. We applied this method for the calculation of the fluorescence spectrum of the Pr3+ ions in phosphate materials. The transition probability of the fluorescence was calculated in the same manner of the absorption. The obtained theoretical fluorescence spectrum was in good agreement with the experimental one, though the intensity of each peak was deeply dependent on the configuration of the surrounding structural units. The results suggested that the DVME method was useful for the calculation of not only absorption but also fluorescence spectra of rare‐earth ions in oxide materials. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2009
NMR computations for carbon nanotubes from first principles: Present status and future directions
Authors: Zurek Eva , Autschbach Jochen 
Published: May 2009

AbstractNMR (nuclear magnetic resonance) is a versatile experimental tool to study the properties of molecules and solids. It has been proposed that reliable computational data of the 13C NMR chemical shifts of different types of carbon nanotubes may be used to guide experimental characterization by NMR. Within the last few years this field has become quite active. After outlining the background for first‐principles calculations, as well as early model calculations, we focus on recent first‐principles theoretical studies performed toward this end. Studies on finite and infinite SWNT systems have indicated that 13C NMR may be used to determine the diameter distribution of the tubes in a bulk sample. The Knight shift of metallic tubes has been examined. NICS (nucleus independent chemical shifts) have yielded information about the aromaticity of various systems, and the NMR chemical shifts of small molecules trapped in nanotubes have been calculated. Work on SWNTs functionalized with NR groups has suggested that 13C NMR may be used to determine which nanotube carbons are derivatized, and perhaps even yield information about the diameter of the tubes. It has also been found that 13C NMR may be useful to quantify the degree of fluorination. Studies on Stone–Wales defects have indicated that well‐resolved NMR signals may arise from atoms in the defect site. Shielding tensor data is also discussed. The theoretical progress made in this field shows that a wealth of information is contained within the NMR chemical shifts of carbon nanotubes. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2009
Examining the ecological consequences of restoring flow intermittency to artificially perennial lowland streams: Patterns and predictions from the Broken—Boosey creek system in northern Victoria, Australia
Authors: Reich Paul , McMaster Damien , Bond Nick , Metzeling Leon , Lake P. Sam 
Published: May 2009

AbstractThe reinstatement of natural flow regimes is a rapidly emerging issue in river restoration worldwide. In northern Victoria, Australia, efforts are presently underway to restore a natural, intermittent flow regime to several streams which have received perennial diversions for both irrigation and stock and domestic water‐supplies for over 100 years. A pipeline to deliver water to landholders will significantly reduce transmission losses throughout the system allowing irrigation canals and diversion weirs to be decommissioned. The motivation for flow alteration in this system lies primarily in reducing inefficiencies in water delivery which, in turn, will be used to meet escalating demands on water resources. The ecological impact of the flow regime shift on these streams is likely to be substantial. This study utilized an existing artificial hydrological gradient (from perennial to intermittent) in two creek systems, to explore relationships between flow regime and a range of ecological variables. These data provide a benchmark against which to assess ecological changes once flow has been altered and form the basis for predicting changes that can assist future management decisions. Data collected from 10 sites across a strong hydrological gradient detected clear differences in geomorphology, water quality and biotic assemblages (macrophytes, macroinvertebrates and fish). By examining the relationship between flow regime and the distribution of biota we identify both the positive and negative outcomes of restoring naturally intermittent flow regimes within artificially perennial lowland streams. The reinstatement of intermittent flow regimes in artificially perennial streams will continue in many parts of the world as water delivery via these systems becomes increasingly uneconomical. While flow restoration may in principle be regarded as a positive step, these findings emphasize the need to consider fully the ecological consequences of restoring historical hydrological regimes to streams within the context of other human induced catchment disturbances. Copyright © 2009 John Wiley & Sons, Ltd.
The onset of convection in a binary viscoelastic fluid saturated porous layer
Authors: Malashetty M.S. , Swamy M. , Heera R. 
Published: May 2009

AbstractThe onset of convection in a binary viscoelastic fluid‐saturated porous layer is studied using a linear and a weak nonlinear stability analyses. The modified Darcy‐Oldroyd model is employed as a momentum equation. The onset criterion for stationary, oscillatory, and finite amplitude convection is derived analytically. There is a competition between the processes of thermal, solute diffusions, and viscoelasticity that causes the convection to set in through oscillatory rather than stationary. The effect of solute Rayleigh number, Prandtl number, diffusivity ratio, relaxation, and retardation parameters on the stability of the system is investigated. The nonlinear theory based on the truncated representation of Fourier series method is used to find the heat and mass transfer. The effect of various parameters on heat and mass transfer is also brought out. The transient behaviour of the Nusselt number and Sherwood number is investigated by solving the finite amplitude equations using Runge‐Kutta method.
Natural convection between two horizontal coaxial cylinders
Authors: Passerini A. , Růžička M. , Thäter G. 
Published: May 2009

AbstractThe objective of our paper is to start the theoretical investigation of the most commonly used mathematical model for natural convection in a horizontal annulus. First, one shows existence of solutions for the unsteady problem. Then, for any Prandtl number and inverse relative gap width, existence, and stability of a steady solution is proved, provided that the Rayleigh number is sufficiently small. The same is also proved for any Rayleigh number provided the inverse relative gap width is sufficiently small. Furthermore, exponential decay to the steady symmetric solution and uniqueness hold true under stronger restrictions to the Rayleigh number.
Closed‐form solution for an orthotropic elastic strip with a crack perpendicular to the edges under arbitrary anti‐plane shear
Authors: Li X.‐F. , Lee K.Y. 
Published: May 2009

AbstractA cracked orthotropic elastic strip of finite width is analyzed under antiplane shear loading. For four frequently encountered constraint edges, i.e. free‐free, clamped‐clamped, free‐clamped, or clamped‐free edges, the Fourier series method is used to reduce triple series equations, and then to a mixed boundary value problem associated with a mode‐III crack for each case to a singular integral equation. Closed‐form solutions are derived for the resulting equations, and formulae for calculating stress intensity factors are obtained for an internal crack and edge cracks subjected to arbitrarily varying loading. Numerical results of the stress intensity factors for an eccentric, central, and edge crack are shown graphically for the case of uniform loading at the crack faces. Obtained formulae for determining stress intensity factors can be taken as a benchmark of numerical evaluations. The derived results are also applicable to an isotropic elastic strip with an anti‐plane shear crack normal to the edges.
Total Pelvic Exenteration for Primary and Recurrent Malignancies
Authors: Ferenschild F. T. J. , Vermaas M. , Verhoef C. , Ansink A. C. , Kirkels W. J. , Eggermont A. M. M. , de Wilt J. H. W. 
Published: May 2009

AbstractIntroductionComplete resection is the most important prognostic factor in surgery for pelvic tumors. In locally advanced and recurrent pelvic malignancies, radical margins are sometimes difficult to obtain because of close relation to or growth in adjacent organs/structures. Total pelvic exenteration (TPE) is an exenterative operation for these advanced tumors and involves en bloc resection of the rectum, bladder, and internal genital organs (prostate/seminal vesicles or uterus, ovaries and/or vagina).MethodsBetween 1994 and 2008, a TPE was performed in 69 patients with pelvic cancer; 48 with rectal cancer (32 primary and 16 recurrent), 14 with cervical cancer (1 primary and 13 recurrent), 5 with sarcoma (3 primary and 2 recurrent), 1 with primary vaginal, and 1 with recurrent endometrial carcinoma. Ten patients were treated with neoadjuvant chemotherapy and 66 patients with preoperative radiotherapy to induce down‐staging. Eighteen patients received IORT because of an incomplete or marginal complete resection.ResultsThe median follow‐up was 43 (range, 1–196) months. Median duration of surgery was 448 (range, 300–670) minutes, median blood loss was 6,300 (range, 750–21,000) ml, and hospitalization was 17 (range, 4–65) days. Overall major and minor complication rates were 34% and 57%, respectively. The in‐hospital mortality rate was 1%. A complete resection was possible in 75% of all patients, a microscopically incomplete resection (R1) in 16%, and a macroscopically incomplete resection (R2) in 9%. Five‐year local control for primary locally advanced rectal cancer, recurrent rectal cancer, and cervical cancer was 89%, 38%, and 64%, respectively. Overall survival after 5 years for primary locally advanced rectal cancer, recurrent rectal cancer, and cervical cancer was 66%, 8%, and 45%.ConclusionsTotal pelvic exenteration is accompanied with considerable morbidity, but good local control and acceptable overall survival justifies the use of this extensive surgical technique in most patients, especially patients with primary locally advanced rectal cancer and recurrent cervical cancer.
Reactions to and Desire for Prognostic Testing in Choroidal Melanoma Patients
Authors: Beran Tammy M. , McCannel Tara A. , Stanton Annette L. , Straatsma Bradley R. , Burgess Barry L. 
Published: May 2009

AbstractTo determine if choroidal melanoma patients want cytogenetic prognostic information. Ninety‐nine choroidal melanoma patients completed a questionnaire regarding their opinions about receiving prognostic information. The perceived usefulness of prognostic information was evaluated in patients who had undergone cytogenetic testing. Depressive symptoms, quality of life, and interest in supportive counseling during test receipt were assessed. Ninety‐seven percent of respondents reported that they would have wanted prognostic information at the time of their treatment and 98% of respondents reported that supportive counseling should be offered when prognostic information is given. Patients who had received a more favorable prognostic result were more likely to endorse the usefulness of cytogenetic testing than were patients who had received a less favorable prognostic result. Psychological status did not vary significantly as a function of cytogenetic test result. Prognostic information was important to patients with choroidal melanoma, even in the absence of prophylactic measures which might improve prognosis.
Characterization of Turkish Virgin Olive Oils Produced from Early Harvest Olives
Authors: Dıraman Harun , Dibeklioğlu Hamdi 
Published: May 2009

AbstractOlives were collected from various districts of Turkey (North and South Aegean sub‐region, Bursa‐Akhisar, South East Anatolia region) harvested over seven (2001–2007) seasons. The aim of this study was to characterize the chemical profiles of the oils derived from single variety Turkish olives including Ayvalik, Memecik, Gemlik, Erkence, Nizip Yaglik and Uslu. The olive oils were extracted by super press and three phase centrifugation from early harvest olives. Chosen quality indices included free fatty acid content (FFA), peroxide value (PV) and spectrophotometric characteristics in the ultraviolet (UV) region. According to the FFA results, 46% (11 out of 24 samples) were classified as extra virgin olive oils; whereas using the results of PV and UV, over 83% (over 19 of the 24 samples) had the extra virgin olive oil classification. Other measured parameters included oil stability (oxidative stability, chlorophyll pigment, pheophytin‐α), cis–trans fatty acid composition and color index. Oxidative stability among oils differed whereas the cis–trans fatty acid values were within the national and international averages. Through the application of two multivariate statistical methods, Principal component and hierarchical analyses, early harvest virgin olive oil samples were classified according to the geographical locations categorized in terms of fatty acid profiles. Such statistical clustering gave rise to defined groups. These data provide evidence of the variation in virgin olive oil quality, especially early harvest and cis–trans isomers of fatty acid profiles from the diverse agronomic conditions in the olive growing regions of Turkey.