bluuebunny/crossref_metadata_2025_split huggingface dataset:
Multiscale domain decomposition analysis of quasi‐brittle heterogeneous materials
Authors: Lloberas‐Valls O. , Rixen D.J. , Simone A. , Sluys L.J. 
Published: November 2011

SUMMARYA hybrid multiscale framework is presented, which processes the material scales in a concurrent manner, borrowing features from hierarchical multiscale methods. The framework is used for the analysis of non‐linear heterogeneous materials and is capable of tackling strain localization and failure phenomena. Domain decomposition techniques, such as the ﬁnite element tearing and interconnecting method, are used to partition the material in a number of non‐overlapping domains and adaptive reﬁnement is performed at those domains that are affected by damage processes. This reﬁnement is performed in terms of material scale and ﬁnite element size. It is veriﬁed that the results are independent of the chosen domain decomposition. Moreover, the multiscale analyses are validated with reference solutions obtained with a full ﬁne‐scale solution procedure. Copyright © 2011 John Wiley & Sons, Ltd.
A polarization‐based FFT iterative scheme for computing the effective properties of elastic composites with arbitrary contrast
Authors: Monchiet V. , Bonnet G. 
Published: November 2011

SUMMARYIt is recognized that the convergence of FFT‐based iterative schemes used for computing the effective properties of elastic composite materials drastically depends on the contrast between the phases. Particularly, the rate of convergence of the strain‐based iterative scheme strongly decreases when the composites contain very stiff inclusions and the method diverges in the case of rigid inclusions. Reversely, the stress‐based iterative scheme converges rapidly in the case of composites with very stiff or rigid inclusions but leads to low convergence rates when soft inclusions are considered and to divergence for composites containing voids. It follows that the computation of effective properties is costly when the heterogeneous medium contains simultaneously soft and stiff phases. Particularly, the problem of composites containing voids and rigid inclusions cannot be solved by the strain or the stress‐based approaches. In this paper, we propose a new polarization‐based iterative scheme for computing the macroscopic properties of elastic composites with an arbitrary contrast which is nearly as simple as the basic schemes (strain and stress‐based) but which has the ability to compute the overall properties of multiphase composites with arbitrary elastic moduli, as illustrated through several examples. Copyright © 2011 John Wiley & Sons, Ltd.
A stochastic simulation method for uncertainty quantification in the linearized inverse conductivity problem
Authors: Polydorides N. 
Published: November 2011

SUMMARYThis paper considers the inverse problem in electrical impedance tomography with non‐informative prior information on the required conductivity function. The problem is approached with a Newton‐type iterative algorithm where the solution of the linearized approximation is estimated using Bayesian inference. The novelty of this work focuses on maximum a posteriori estimation assuming a model that incorporates the linearization error as a random variable. From an analytical expression of this term, we employ Monte Carlo simulation in order to characterize its probability distribution function. This simulation entails sampling an improper prior distribution for which we propose a stable scheme on the basis of QR decomposition. The simulation statistics show that the error on the linearized model is not Gaussian, however, to maintain computational tractability, we derive the posterior probability density function of the solution by imposing a Gaussian kernel approximation to the error density. Numerical results obtained through this approach indicate the superiority of the new model and its respective maximum a posteriori estimator against the conventional one that neglects the impact of the linearization error. Copyright © 2011 John Wiley & Sons, Ltd.
Shifted FSAI preconditioners for the efficient parallel solution of non‐linear groundwater flow models
Authors: Ferronato M. , Janna C. , Pini G. 
Published: November 2011

SUMMARYThe present paper investigates the performance of a shifted factorized sparse approximate inverse as a parallel preconditioner for the iterative solution to the linear systems arising in the finite element discretization of non‐linear groundwater flow models. The shift strategy is based on an inexpensive preconditioner update exploiting the structure of the coefficient matrix. The proposed algorithm is experimented with in the parallel simulation of a large‐scale real multi‐aquifer system characterized by a stochastic distribution of the hydraulic conductivity. The numerical results show that the shifted factorized sparse approximate inverse algorithm may yield an overall computational gain up to 300% with respect to the non‐shifted scheme with an excellent parallel efficiency. Copyright © 2011 John Wiley & Sons, Ltd.
A new bipenalty formulation for ensuring time step stability in time domain computational dynamics
Authors: Hetherington Jack , Rodríguez‐Ferran Antonio , Askes Harm 
Published: November 2011

SUMMARYIt is well known that use of standard penalty methods can decrease the critical time step of time domain dynamic finite element analyses. The bipenalty method utilises both stiffness and mass penalties to impose constraints that have a minimal effect on the eigenfrequencies of the finite element system. One way of achieving this goal is to find a ratio of stiffness and mass penalty parameters—the critical penalty ratio (CPR)—that does not affect the maximum eigenfrequency (and therefore, for conditionally stable solution schemes, the critical time step) of a system. In this contribution, we develop a new method of calculating the CPR associated with a finite element formulation by examining the eigenvalue problem in detail. Advantages of the method compared with previous solutions include increased simplicity and generality and the ability to consider multiple constraints. The method is demonstrated by deriving CPRs for a few finite element formulations, which are then verified using simple numerical examples. The superiority of the bipenalty method over standard mass penalty methods is also demonstrated. Copyright © 2011 John Wiley & Sons, Ltd.
Limitations of Cl2/O2‐based ICP‐RIE of deep holes for planar photonic crystals in InP
Authors: Kaspar Peter , Fougner Christopher , Kappeler Roman , Jäckel Heinz 
Published: November 2011

AbstractA detailed study of dry‐etching of high‐aspect‐ratio holes into an indium phosphide substrate is presented for a Cl2/O2‐based plasma chemistry. The etching is performed in an inductively coupled plasma reactive ion etching reactor. The separate influence of the various etching parameters on the quality of the etched holes is identified. Quality measures such as high aspect ratio, hole cylindricity and verticality as well as sidewall smoothness can be controlled by varying the ICP power, the relative O2 flow rate and the self‐bias of the plasma. We were able to clearly identify trade‐offs that have to be made and limitations of the etching chemistry/technology used: If the aspect ratio improves, then the cylindricity also improves, whereas the verticality and the sidewall smoothness degrade. In previous reports, a certain ambiguity is generally observed in the sense that different process parameters exhibit partially contradicting trade‐offs. We show that this behaviour can be remedied by a careful selection of the variable parameters. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Short‐wavelength InP quantum cascade laser sources by quasi‐phase‐matched intracavity second‐harmonic generation
Authors: Vizbaras Augustinas , Anders Matthias , Grasse Christian , Katz Simeon , Boehm Gerhard , Meyer Ralf , Belkin Mikhail A. , Amann Markus‐Christian 
Published: November 2011

AbstractShort‐wavelength quantum cascade laser (QCL) sources, based on transversely integrated giant nonlinearity have been designed and fabricated. Devices consist of an injectorless GaInAs/AlInAs/InP pump QCL and a passive two‐well based nonlinearity grown on top of the pump active region. The nonlinearity was designed to possess a giant nonlinear response for the process of second‐harmonic generation (SHG). For efficient SHG process, the wave‐vector mismatch between the fundamental and the nonlinear signals was compensated by structuring the nonlinear layer into the 50% duty‐cycle quasi‐phase‐matching gratings. Using this approach we were able to demonstrate room‐temperature operation at 3.5 µm and 2.7 µm second‐harmonic emission wavelengths with output power levels up to 30 µW. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Design and analysis of a flow control scheme over wireless networks
Authors: Abate Alessandro , Chen Minghua , Wang Yue , Zakhor Avideh , Sastry Shankar 
Published: November 2011

SUMMARYThis paper studies the problem of congestion control on wireless networks. A dynamical model for the end‐to‐end network flow control that exploits the differentiation between congestion loss and physical channel error loss is proposed. The introduction of a specific wireless model is motivated by the distinctive presence of channel errors, which are often not known exactly. We assume that each wireless link is associated with an additional error function that depends on the current flow along the link and that accounts for the packet loss rate caused by the physical channel. This leads to a new dynamic flow control scheme that naturally extends a known mathematical model for the fluid‐flow approximation of the Transmission Control Protocol for wireline networks. The main objective of this work is to study the dynamical properties of the new model: we analyze its nonlinear dynamics, derive its stability properties, and study its robustness to delays. We also present and discuss some ns‐2 simulations of its dynamics. This work additionally looks at the actual implementation of the proposed scheme: by requiring only modifications to the application layer rather than the transport one, no alterations to the network infrastructure or transport protocols are needed. The article argues that the new scheme appears to be not only theoretically meaningful but also practically relevant for an application layer implementation. Copyright © 2011 John Wiley & Sons, Ltd.
Effect of Hydrophobicity of PEO–PPO–PEO Block Copolymers on Micellization and Solubilization of a Model Drug Nimesulide
Authors: Parmar Arpan , Yerramilli Usha , Bahadur Pratap 
Published: November 2011

AbstractThe present work explored the molecular implications governing the solubilization of a model drug nimesulide (NIM) in micelles of ethylene oxide‐propylene oxide (EO–PO) triblock copolymers. The aggregation behavior and solubilization studies on four copolymers each with the same mol mass of central PPO block equal to 2,250 and varying % PEO was examined by means of UV–VIS. Moreover, high‐sensitivity differential scanning calorimetry, and Fourier transform infrared spectrometry measurements were used to evaluate the critical micellization temperature. The solubilization at different temperatures (30, 37, 45 °C), pH (2 to 10) and in the presence of added sodium chloride (0–2 M) was monitored and the partition coefficient (P) and the free energy of solubilization (ΔGso) were calculated. The site of solubilization of NIM in micelles was also probed. The NIM solubility decreased with increases in the PEO molecular weight; the drug resides in the micelle core.
Synthesis and Characterization of New Biodiesels Derived From Oils of Plants Growing in Northern Wisconsin and Minnesota
Authors: Lane James W. , Hukriede Kurt , Jersett Adam , Koirala Damodar , Levings Dan , Stewart Aaron , Waxman Michael A. 
Published: November 2011

AbstractWe report on the preparation and selected properties of some new biodiesels which we synthesized from oils of plants growing in Northern Wisconsin and Minnesota. The composition and the low‐temperature properties such as crystallization onset Tc and end of melting Tm investigated with the help of differential scanning calorimetry are presented. Some of these biodiesels exhibited remarkably good low‐temperature characteristics. In order to further improve these properties, we use a variety of alcohols during the transesterification process, including isopropyl, 2‐butyl, and isoamyl alcohols. Using several parameters such as oil content and crystallization onset temperature Tc, plant species that appear most promising have been identified, among those highbush cranberry (Tc ≈ −31 °C for its methyl esters, Tc ≈ −41 °C for its 2‐butyl esters), dotted horsemint (Tc ≈ −17 °C for its methyl esters, Tc ≈ −40 °C for its 2‐butyl esters), and American hazelnut (Tc ≈ −19 °C for its methyl esters, Tc ≈ −30 °C for its 2‐butyl esters).
The history of the study of bacterial/cyanobacterial forms in phosphorites
Authors: Zanin Yu.N. , Zamirailova A.G. 
Published: November 2011

Abstract
The first bacterial (bacillus-like) form in phosophorites was described by B. Renault and C.E. Bertrand from coprolites of vertebrates in the bituminous shales from the Autun region, France, in 1895. In 1990, B. Renault revealed coccoid bacteria from the same deposits. In 1983, D. Soudry and Y. Champetier described for the first time the capsules of cyanobacterial threads from Campanian phosphorites of the Negev Desert, Israel. Glycocalics was first found in the Upper Jurassic–Lower Cretaceous phosphorites of the Egor’evskoe deposit on the Russian Platform, where it coexists with coccoid bacteria.
The depths of the Early Paleozoic sedimentary basins of the Paleoasian Ocean: lithofacies and bioindicator estimates
Authors: Sennikov N.V. , Obut O.T. , Bukolova E.V. , Tolmacheva T. Yu. 
Published: November 2011

Abstract
Estimating the paleobasin depth is one of the most difficult problems in studying the evolution of sedimentation. Considerable depth variations in ocean and shelf paleobasins are due not only to their origin but also to the evolution of their large constituents owing to the differentiation of the dissected bottom. The Early Paleozoic volcanic-sedimentary and sedimentary rocks of Gorny Altai have been studied from this standpoint. They formed in the paleoceanic rises of the Early Cambrian Kuznetsk–Altai island arc, in the Late Cambrian–Early Ordovician Altai segment of the Paleoasian Ocean, and in the outer zone of the Late Ordovician Altai shelf basin. Geologic, geochemical, and lithofacies data permitted expert estimates of the absolute vertical depths of individual paleobasin fragments with siliceous sedimentation, calibrated at the final stage by bioindicator methods. The upper parts of the paleoceanic rises in the Early Cambrian Kuznetsk–Altai island arc are presumed to occur at depths of 300–400 m; those of the paleoceanic rises in the Late Cambrian–Early Ordovician Altai segment of the Paleoasian Ocean, at depths of 500–1200 m; and the outer edge of the outer zone of the Late Ordovician Altai shelf basin, at depths of 150–500 m.
Sea level changes and rapid crustal movements in cratonic areas in the Late Paleozoic
Authors: Artyushkov E.V. , Chekhovich P.A. 
Published: November 2011

Abstract
In the Phanerozoic, the sea depth in epeiric sedimentary basins showed considerable variations, often accompanied by regression. In periods of regression and erosion, the subaerially exposed shelf and the adjacent parts of the marine basins gave rise to numerous nonstructural (stratigraphic) hydrocarbon traps. Sea depth variations with a magnitude of up to 100–200 m and 1–3 myr long (third-order cycles) are usually attributed to the eustatic fluctuations of the sea level. To estimate their possible range, a model is proposed which describes the water depth variations as a function of eustatic fluctuations in tectonically subsiding carbonate platforms. We take into account the crustal isostatic response to the changing water load and the finite time necessary for soil and karst formation in the exposed shelf or its upper part. This model allowed analyzing data on the reference sections of the North Timan shallow-water sediments. According to the analysis, the third-order sea level changes in the Middle Carboniferous, Late Carboniferous, and Early Permian did not exceed several tens of meters. During the same period, shorter fluctuations (∼100 kyr) occurred owing to the waxing and waning of large Gondwanan ice sheets. In the first half of the Bashkirian Age (Early Pennsylvanian), regression took place in the East European and North American cratons and then shallow-water sedimentation resumed. This regression is usually attributed to a considerable sea level fall. In some other areas, slow shallow-water sedimentation continued throughout the Bashkirian. This suggests that the Bashkirian regression was due to the crustal uplifts. Short-term uplifts can be explained by ascending convective currents beneath the asthenosphere. In southern North America, they brought an active fluid into the lithosphere. This caused rapid eclogitization-related crustal subsidence in the Arkoma and Anadarko basins as well as intense lithospheric weakening and shortening in the Ouachita Fold Belt.
The phase state of NaF-containing fluid at 700 °C and 1, 2, and 3 kbar (from the results of study of synthetic fluid inclusions in quartz)
Authors: Kotel’nikova Z.A. , Kotel’nikov A.R. 
Published: November 2011

Abstract
Fluid inclusions containing NaF have been extracted by healing quartz cracks at 700 °C and 1, 2, and 3 kbar. The aqueous NaF solutions belong to P–Q-type systems. They are characterized by the existence of two stable and one metastable immiscibility regions. Study of the inclusions showed that under these conditions, the fluid was in the heterogeneous state. The least dense phase detected in two-phase inclusions with the largest vapor bubble is an undersaturated aqueous solution. Its salt content points to a chemical interaction of NaF with quartz, which led to a change in the component composition of the system. As temperature grows, the highly viscous liquid of the inclusions segregates, and a new phase appears either around the vapor bubble or near the inclusion walls. At 3 kbar, one more type of inclusions with a vitreous phase forms, which shows anomalous behavior on heating. The phase changes in these inclusions can be interpreted only tentatively. Based on the data obtained, we suggest the existence of quasi-polymer compounds containing sodium hydrosilicates, in which OH– groups are partly substituted by F–. The results obtained are applied to study of natural processes involving fluids belonging to the P–Q-type systems.
H2O and CO2 in parental magmas of Kliuchevskoi volcano inferred from study of melt and fluid inclusions in olivine
Authors: Mironov N.L. , Portnyagin M.V. 
Published: November 2011

Abstract
This paper reports new FTIR data on the H2O and CO2 concentrations in glasses of 26 naturally quenched and experimentally partially homogenized melt inclusions in olivine (Fo85–91) phenocrysts from rocks of the Kliuchevskoi volcano. Measured H2O concentrations in the inclusions range from 0.02 to 4 wt.%. The wide variations in the H2O content of the inclusions, which do not correlate with the host olivine composition and contents of major elements in the melts, are explained by the H2O escape from inclusions via diffusion through the host olivine during the magma eruption and the following cooling. The largest H2O loss is characteristic of inclusions from lava samples which cooled slowly after eruption. The minimal H2O loss is observed for inclusions from rapidly quenched pyroclastic rocks. Parental magmas of the Kliuchevskoi volcano are estimated to contain 3.5 wt.% H2O. The new data imply a 40 °C lower mantle temperatures than that estimated earlier for the Kliuchevskoi primary melts. The concentrations of CO2 in glasses range from &lt;0.01 to 0.13 wt.% and do not correlate with the type of studied inclusions and their composition. The calculated pressures of melt equilibria with H2O–CO2 fluid inside the inclusions are lower than 270 MPa. They are significantly lower than a pressure of 500 MPa calculated from the density (~0.8 g/cm3) of cogenetic fluid inclusions in high-Fo olivine. The significant pressure drop inside the melt inclusions after their trapping in olivine might be due to the H2O loss and redistribution of CO2 from melt to daughter fluid phase. Compared with melt inclusions, cogenetic fluid inclusions provide independent information about the crystallization pressures of olivine and initial CO2 content in the Kliuchevskoi magma, which were estimated to be at least 500 MPa and 0.35 wt.%, respectively. The maximum CO2 concentrations in the primary Kliuchevskoi melts are estimated at 0.8–0.9 wt.%. The decompression crystallization of the Kliuchevskoi magmas starts at depths of 30–40 km and proceeds with a continuous decrease in CO2 content and an increase (up to 6–7 wt.%) and then a decrease (at &lt;300 MPa) in H2O content in melts, which explains the origin of the whole spectrum of rocks and melt inclusions of the Kliuchevskoi volcano.
© 2011, V.S. Sobolev IGM, Siberian Branch of the RAS. Published by Elsevier B.V. All rights reserved.
Rb–Sr isotope system and Rb–Sr partitioning in the rocks of the Ary-Bulak ongonite massif, formed with the participation of fluoride–silicate magmatic immiscibility
Authors: Peretyazhko I.S. , Savina E.A. , Dril’ S.I. , Gerasimov N.S. 
Published: November 2011

Abstract
The rocks of the Ary-Bulak ongonite massif (eastern Transbaikalia) have widely varying Rb (1499–4274 ppm) and Sr (10–2654 ppm) contents. In passing from porphyritic ongonites to aphyric rocks at the endocontact, Rb content increases by two to three times; Sr content, by two to three orders of magnitude. Feldspars and Fe-rich micas are the major Rb carriers and concentrators. The aphyric rocks accumulate Rb, because the weight percentage of sanidine in their total mineral balance increases relative to that in the porphyritic ongonites. In the latter, Sr is relatively uniformly distributed over the phenocrysts and groundmass. Prosopite and products of the quenching (glass) and partial crystallization of a calcium fluoride melt accumulate a considerable amount of Sr. The presence of these phases in the porphyritic and aphyric rocks abnormally increases their Sr content. The Rb content of silicate glass in melt inclusions (MI) varies much more widely (634 ppm—3.17 wt.%) than that of the massif rocks (1435–4309 ppm), especially in terms of the maximum value. Most of silicate glass in the MI is much poorer in Sr (&lt;1–2 ppm) than the rocks. The highest Sr content (376–422 ppm) was detected in silicate glass from a MI with segregations of immiscible fluoride glass.
Rubidium–strontium isotope dating confirmed the Early Cretaceous (141.6 ± 0.5 Ma) age of all the massif rocks, with (87Sr/86Sr)0 = 0.70817 ± 0.00025, that is, intermediate between mantle and typical crustal values. A near-linear dependence has been detected between 1/Sr and 87Sr/86Sr, which is usually interpreted as a false isochron and explained by models involving mixed components with different 87Sr/86Sr. According to calculations of the weight percentage of Sr isotopes in the massif rocks, this linear dependence is explained by Sr and Rb partitioning in ongonitic magma, which has the same initial Sr isotope ratio.
Only fluoride–silicate liquid immiscibility determined the Rb and Sr partitioning in ongonitic magma and, correspondingly, the subsequent evolution of the Rb–Sr isotope system in the Ary-Bulak massif rocks. This immiscibility (liquation) in ongonitic magma might have created very special rocks, abnormally enriched in Ca, F, and Sr, even if the initial homogeneous silicate melt was relatively poor in these elements. The relatively small initial isotope ratio (87Sr/86Sr)0 ≈ 0.708 in the massif rocks does not contradict the hypothesis of the intense heating of a F-enriched crustal substrate and the formation of a rare-metal granitoid melt chamber (from which the residual ongonitic melt was produced) under the thermal effect of deep-seated basaltoid magma.