bluuebunny/crossref_metadata_2025_split huggingface dataset:
Numerical analysis of frost effects in porous media. Benefits and limits of the finite element poroelasticity formulation
Authors: Multon Stéphane , Sellier Alain , Perrin Bernard 
Published: January 2011

SUMMARYThe aim of this paper is to analyse the performance of a finite element formulation usable for predicting the mechanical consequences of frost effects on porous media. It considers the characteristics of porous media and how the frost action can be assessed. The problem is then separated into two parts: thermal and poromechanical calculations. The constitutive equations developed in the framework of poromechanics are presented and the implementation in a usual finite element poroelasticity formulation based on Zuber's method is adopted. An analysis of the time‐step influence on the convergence rate is given and leads us to propose a simple method in order to obtain objectivity of the finite element response and avoid over‐long calculations. Frost effect simulations are carried out on real porous media (two fired clays) as a case study. Although the experimental behaviour of the porous media subjected to frost action is in accordance with some observations, the calculated strains appear to be overestimated compared with measurements. The problem could be largely attributable to the difficulty of assessing permeability evolution during frost development. Copyright © 2011 John Wiley & Sons, Ltd.
Simulating fracture propagation in rock and concrete by an augmented virtual internal bond method
Authors: Zhang Zhennan , Gao Huajian 
Published: January 2011

SUMMARYThis paper develops a practical approach to simulating fracture propagation in rock and concrete based on an augmented virtual internal bond (VIB) method in which the cohesion of solid is modeled as material particles interconnected by a network of randomized virtual micro bonds described by the Xu–Needleman potential. The micro bond potential is used to derive macroscale constitutive relations via the Cauchy–Born rule. By incorporating different energy contributions due to stretch and shearing, as well as different energy levels under tension and compression of each micro bond, the derived macro constitutive laws are particularly useful for modeling quasi‐brittle materials such as rock and concrete which usually have different Poisson ratios and much higher compressive strength than tensile strength. The mesh‐size sensitivity associated with strain‐softening in the present constitutive model is addressed by adjusting material constants near the crack tip so that the biJ‐integral is kept equal to the intrinsic fracture energy of the material. Numerical examples demonstrate that the proposed VIB method is capable of simulating mixed mode fracture propagation in rock and concrete with results in consistency with relevant experimental observations. Copyright © 2011 John Wiley & Sons, Ltd.
Validation of the urinary sensation scale (USS)
Authors: Coyne Karin S. , Margolis Mary Kay , Hsieh Ray , Vats Vasudha , Chapple Christopher R. 
Published: January 2011

AbstractAimThe purpose of this study was to assess the validity of the Urinary Sensation Scale (USS) in men with overactive bladder and voiding symptoms (OAB‐LUTS) and women with overactive bladder (OAB).MethodsData from two OAB clinical trials of tolterodine were used. The USS, a 5‐point scale, assesses the amount of urinary urgency associated with each urination. Three methods to calculate the USS are: mean urgency (Mean USS); mode urgency (Mode USS); and sum urgency (sum USS). The validity and responsiveness of the scoring methods was assessed using Spearman's correlations, general linear models, and effect sizes.ResultsData from 650 men (Study 1) and 413 women (Study 2) were analyzed. Mean age was 65.2 (men) and 47.8 (women); 70% were Caucasian in both studies. Correlations of USS scores with bladder diary variables were small to moderate and higher among Sum USS than Mean USS (r = 0.02–0.64). Correlations among the USS and patient‐reported outcomes (PROs) were again small to moderate and higher with Sum USS (r = 0.05–0.41). Both the Mean USS and Sum USS significantly discriminated (all P < 0.001) among all bladder diary variables (except nocturia and UUI in men) when grouped as improved/not improved as well as by the PROs. Effect sizes for men and women, respectively, were −0.52 and −1.09 for Mean USS and −0.72 and −1.36 for Sum USS.ConclusionThe USS is a valid and highly responsive measure of urinary urgency in men with OAB‐LUTS and women with OAB. Neurourol. Urodynam. 30:360–365, 2011. © 2011 Wiley‐Liss, Inc.
Innervation of parasympathetic postganglionic neurons and bladder detrusor muscle directly after sacral root transection and repair using nerve transfer
Authors: Barbe Mary F. , Ruggieri Michael R. 
Published: January 2011

AbstractAimsThis is a continuation of studies examining the effectiveness of root repairs and nerve transfers for bladder reinnervation. Our previous retrograde fluorogold tracing studies from the bladder to the spinal cord found regrowth of axons from the spinal cord through the nerve repair site to the bladder which was confirmed electrophysiologically [Ruggieri et al. J Neurotrauma 25:214–24, 2006]. The current study determines whether the pattern of axonal regrowth from the repaired nerves or roots to the bladder is different between the surgical reanastomosis methods.MethodsThe canine bladder was denervated by transection of all nerve roots from the sacral spinal cord mediating bladder contraction. Reinnervation surgeries included end‐on‐end repair of transected sacral ventral roots, transfer of coccygeal to sacral ventral roots (CG NT), or transfer of genitofemoral to pelvic nerves (GF NT).ResultsPostmortem dialkylcarbocyanine dye tracing with Neurotrace DiI from the distal pelvic nerve to the bladder wall, combined with PGP9.5 neuronal immunohistochemistry, demonstrated innervation by DiI‐labeled axons of only parasympathetic postganglionic intramural ganglia in normal controls and sham operated controls, but reinnervation of both intramural ganglia and detrusor muscle directly after repair of sacral ventral roots. GF NT and CG NT also resulted in reinnervation of both intramural ganglia and detrusor muscle, although to a lesser extent than repaired roots.ConclusionsBladder reinnervation with either the same nerve (orthotopic reinnervation) or with either a primarily somatic nerve (coccygeal) or a primarily sensory nerve (genitofemoral) results in reinnervation of both intramural ganglia as well as direct innervation of detrusor muscle. 30:599–605, 2011. © 2011 Wiley‐Liss, Inc.
Superparamagnetic iron oxide (SPIO) labeling efficiency and subsequent MRI tracking of native cell populations pertinent to pulmonary heart valve tissue engineering studies
Authors: Ramaswamy Sharan , Schornack Paul A. , Smelko Adam G. , Boronyak Steven M. , Ivanova Julia , Mayer John E. , Sacks Michael S. 
Published: January 2011

SUMMARYThe intimal and medial linings of the pulmonary artery consist largely of vascular endothelial cells (VECs) and vascular smooth muscle cells (VSMCs), respectively. The migration of these cell types to a potential tissue‐engineered pulmonary valve (TEPV) implant process is therefore of interest in understanding the valve remodeling process. Visualization and cell tracking by MRI, which employs hypointense contrast achievable through the use of superparamagnetic iron oxide (SPIO) microparticles to label cells, provides a method in which this can be studied. We investigated the SPIO labeling efficiency of human VECs and VSMCs, and used two‐ and three‐dimensional gradient echo sequences to track the migration of these cells in agar gel constructs. Protamine sulfate (4.5 µg/mL) was used to enhance SPIO uptake and was found to have no influence on cell viability or proliferation. MRI experiments were initially performed using a 9.4‐T scanner. The results demonstrated that the spatial positions of hypointense spots were relatively unchanged over 12 days. Subsequent MR experiments performed at 7 T demonstrated that three‐dimensional imaging provided the best spatial resolution to assess cell fate. R2* maps were bright in SPIO cell‐encapsulated gels in comparison with unlabeled counterparts. Signal voids were ruled out as hypointense regions owing to the smooth exponential decay of T2* in these voxels. As a next step, we intend to use the SPIO cell labeling and MR protocols established in this study to assess whether hemodynamic stresses will alter the vascular cell migratory patterns. These studies will shed light on the mechanisms of vascular remodeling after TEPV implantation. Copyright © 2011 John Wiley & Sons, Ltd.
X‐ray diffraction, Raman, and differential thermal analyses of the thermal aging of a Kevlar®‐PBI blend fabric
Authors: Arrieta Carlos , David Eric , Dolez Patricia , Vu‐Khanh Toan 
Published: January 2011

AbstractA previous study of the effects of thermal aging on the tensile properties of a fabric made of a 60–40 wt % blend of Kevlar and PBI fibers has shown that exposure to elevated temperatures between 190 and 320°C results in a rapid decrease in tensile breaking force retention. In this article, X‐ray diffraction and Raman spectroscopy analyses were carried out to evaluate the consequences of thermal aging on the material's crystallinity. Differential thermal analyses were also undertaken to examine the evolution of the glass transition temperature of PBI following thermal exposure. X‐ray diffraction profiles show a gradual increase in the crystallinity with temperature and aging time, whereas a complete disappearance of spectral lines for aged samples in Raman analysis suggests instead a decrease in crystallinity as a consequence of exposure to elevated temperatures. The seemingly contradictory outcome obtained when using the two techniques led to the proposal of a new, alternative hypothesis to explain the observed results. This hypothesis involves two simultaneous events that occur during thermal aging: the increase of crystallite size in the direction parallel to coplanar sheets, and the disruption of the crystalline lattice in the direction perpendicular to those sheets. The glass transition temperature of PBI was found to shift towards the lower temperatures after thermal aging, a phenomenon that can be associated with random polymer chain scission caused by thermal aging. POLYM. COMPOS., 2011. © 2011 Society of Plastics Engineers
Study of nanoreinforced shape memory polymers processed by casting and extrusion
Authors: Richardson Tara B. , Mosiewicki Mirna A. , Uzunpinar Cihan , Marcovich Norma E. , Aranguren Mirta I. , Kilinc‐Balci Fatma , Broughton Roy M. , Auad Maria L. 
Published: January 2011

AbstractMulti‐walled carbon nanotubes (CNTs) and cellulose nanofibers (CNFs) reinforced shape memory polyurethane (PU) composite fibers and films have been fabricated via extrusion and casting methods. Cellulose nanofibers were obtained through acid hydrolysis of microcrystalline cellulose. This treatment aided in achieving stable suspensions of cellulose crystals in dimethylformamide (DMF), for subsequent incorporation into the shape memory matrix. CNTs were covalent functionalized with carboxyl groups (CNT‐COOH) and 4,4′‐methylenebis (phenylisocyanate) (MDI) (CNT‐MDI) to improve the dispersion efficiency between the CNT and the polyurethane. Significant improvement in tensile modulus and strength were achieved by incorporating both fillers up to 1 wt% without sacrificing the elongation at break. Electron microscopy was used to investigate the degree of dispersion and fracture surfaces of the composite fibers and films. The effects of the filler (type and concentration) on the degree of crystallinity and thermal properties of the hard and soft segments that form the PU sample were studied by calorimetry. Overall, results indicated that the homogeneous dispersion of nanotubes and cellulose throughout the PU matrix and the strong interfacial adhesion between nanotubes and/or cellulose and the matrix are responsible for the enhancement of mechanical and shape memory properties of the composites. POLYM. COMPOS., 2011. © 2011 Society of Plastics Engineers
Placental volume and three‐dimensional power Doppler analysis in prediction of pre‐eclampsia and small for gestational age between Week 11 and 13 weeks and 6 days of gestation
Authors: Odeh Marwan , Ophir Ella , Maximovsky Olga , Grinin Vitali , Bornstein Jacob 
Published: January 2011

AbstractObjectiveTo assess three‐dimensional placental volume measurement and three‐dimensional power Doppler (3D‐PD) indices between 10 weeks and 6 days and 13 weeks and 6 days in predicting pregnancy‐induced hypertension (PIH) and small for gestational age (SGA).MethodsThree hundred and eight women undergoing fetal nuchal translucency measurement were prospectively assessed using three‐dimensional ultrasound in order to measure placental volume and 3D‐PD indices: vascularization index (VI), flow index (FI) and vascularization flow index (VFI), using the VOCAL software. The outcome was scored as normal, PIH, SGA or both.ResultsEight women developed PIH and ten delivered SGA; and 17 developed PIH or SGA. The age, gestational age at the examination or delivery, number of the pregnancy and the nuchal translucency, were similar in all groups. The placental volume, FI and VFI were similar between the groups. The VI was significantly lower when PIH developed (7.86 ± 3.92 vs. 12.02 ± 7.09 in the normal group, P = 0.035). The crown‐rump length (CRL) was significantly smaller in the group where either PIH or SGA developed compared to normal outcome (54.29 ± 6.50 and 59.04 ± 8.89, respectively, P = 0.02).ConclusionPlacental volume is not appropriate for early prediction of PIH or SGA, whereas the VI may be of some potential in detection of PIH. The significance of small CRL in these patients should be further tested. Copyright © 2011 John Wiley & Sons, Ltd.
Soluble high‐Tg polyetherimides with good flame retardancy based on an asymmetric phosphinated etherdiamine
Authors: Lin Ching Hsuan , Chang Sheng Lung , Cheng Po Wen 
Published: January 2011

AbstractThis study focuses on preparing soluble, high‐Tg polyetherimides (PEIs) with good flame retardancy. To achieve this goal, a phosphinated aminophenol, 1‐(4‐hydroxyphenyl)‐1‐(4‐aminophenyl)‐1‐(6‐oxido‐6H‐dibenz〈c,e〉〈1,2〉oxaphosphorin‐6‐yl)ethane (1), was prepared. Then, an asymmetric etherdiamine, 1‐(4‐(4‐aminophenoxy)phenyl)‐1‐(4‐aminophenyl)‐1‐(6‐oxido‐6H‐dibenz〈c,e〉〈1,2〉oxaphosphorin‐6‐yl)ethane (3), was prepared from the nucleophilic substitution of (1) with 4‐chloronitrobenzene, followed by catalytic hydrogenation. Light colored, tough, and foldable PEIs (5) with good thermal stability, organo‐solubility, and good flame retardancy were synthesized from the condensation of (3) with various aromatic dianhydrides in N,N‐dimethylacetamide, followed by thermal imidization. Properties of the resulting PEIs were evaluated and compared with those of symmetric PEIs (5′) and polyimides (5″). The structure–property relationships were discussed. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011
Synthesis and photovoltaic behaviors of narrow‐band‐gap π‐conjugated polymers composed of dialkoxybenzodithiophene‐ and thiophene‐based fused aromatic rings
Authors: Lee Kwang‐hoi , Lee Ho‐Jin , Morino Kazuhide , Sudo Atsushi , Endo Takeshi 
Published: January 2011

Abstractπ‐Conjugated polymers, PBDT‐CNETT and PBDT‐CNECPDT, were prepared by the Stille cross‐coupling polymerization. Optical and thermal properties of the obtained polymers were investigated by UV–vis spectroscopy and thermogravimetric analysis. PBDT‐CNETT and PBDT‐CNECPDT exhibited very narrow band gaps of 1.39 and 1.13 eV, respectively. Highest occupied molecular orbital energy levels estimated by surface analyzer were −5.17 and −5.11 eV for PBDT‐CNETT and PBDT‐CNECPDT, respectively. The solar cells based on these polymers were evaluated with the cell configuration of ITO/PEDOT‐PSS/polymer:PC61BH/LiF/Al. The power conversion efficiencies of the solar cells were estimated to be 1.57 and 0.16% for PBDT‐CNETT and PBDT‐CNECPDT, respectively. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011
Transitions in the web of heterotic vacua
Authors: Anderson L.B. , Gray J. , Ovrut B.A. 
Published: January 2011

AbstractWe analyze transitions between heterotic vacua with distinct gauge bundles using two complementary methods – the effective four‐dimensional field theory and the corresponding geometry. From the viewpoint of effective field theory, such transitions occur between flat directions of the potential energy associated with heterotic stability walls. Geometrically, this branch structure corresponds to smooth deformations of the gauge bundle coupled to the chamber structure of Kähler moduli space. We demonstrate how such transitions can change important properties of the effective theory, including the gauge symmetry and the massless spectrum. Geometrically, this study is divided into deformations of the vector bundle which preserve the rank of the gauge bundle and those which change the rank. In the latter case, our results provide explicit solutions to a class of Li‐Yau type deformation problems. Finally, we use the framework of stability walls and their effective theory to study Donaldson‐Thomas invariants on Calabi‐Yau threefolds.
Rapid dislocation‐related D1‐photoluminescence imaging of multicrystalline Si wafers at room temperature
Authors: Schmid R. P. , Mankovics D. , Arguirov T. , Ratzke M. , Mchedlidze T. , Kittler M. 
Published: January 2011

AbstractHere we report on a novel method, which allows rapid photoluminescence imaging of band‐to‐band and dislocation‐related radiation, D1, on multicrystalline silicon wafers at room temperature. We demonstrate spatially resolved 5.0 × 5.0 cm2D1‐images, with a resolution of ∼120 µm, within a total recording time of 550 ms. The method provides homogeneous illumination over the whole sample area. Comparison with results from a conventional photoluminescence mapping technique demonstrates the potential of this new method for application as an in‐line wafer characterization technique.
New template based nanoelectrode arrays for organic/inorganic photovoltaic applications
Authors: Gu Diefeng , Baumgart Helmut , Namkoong Gon 
Published: January 2011

AbstractIn this Letter, we report on a new nanofabrication technology to yield highly arrayed nanoelectrodes for organic–inorganic solar cells that promise new levels of performance and efficiency. This technology efficiently controls the effective area of highly arrayed nanoelectrodes and allows for the maximum incorporation of organic materials within the voids. Particularly the 3D parameters such as thickness, spacing, and height of the nanostructures are controlled non‐lithographically by atomic layer deposition technology.magnified imageNew template based device structure with nanoelectrode arrays for organic/inorganic photovoltaic applications.(© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
THRESHOLD FLOWS FOR THE BREAKDOWN OF SEASONALLY PERSISTENT THERMAL STRATIFICATION: SHOALHAVEN RIVER BELOW TALLOWA DAM, NEW SOUTH WALES, AUSTRALIA
Authors: Reinfelds I. , Williams S. 
Published: January 2011

ABSTRACTReduced mixing of deep pools attributable to river regulation and downstream flow suppression can lead to an increase in the magnitude, frequency and duration of thermal stratification in riverine pools over summer. This study monitored hourly temperature profiles with five thermistor loggers in a 15 m deep natural pool over 12 months from May 2005. Detailed bathymetric and topographic survey data and HEC‐RAS hydraulic modelling of layer Richardson numbers were used to extend thermistor observations of flow‐related stratification breakdown in this single deep pool to a 20 km long pool‐riffle dominated river reach below the dam. Reach‐wide breakdown of persistent thermal stratification in deep pools over spring and summer was likely to be achieved by a flow rate of 3000 ML day−1. This flow rate approximates the long‐term mean annual natural flow (2860 ML day−1) and the 16th flow duration percentile (mean daily flows equalled or exceeded for 16% of time), indicating that thermal stratification of the deepest pools in the Shoalhaven River is a common, natural phenomenon not solely attributable to river regulation. Should reasonably consistent hydraulic geometry relationships exist between low salinity rivers in similar climatic, hydrologic and geomorphic settings, then we suggest that the mean annual natural flow is likely to achieve widespread breakdown of thermal stratification across lengthy reaches of similar pool‐riffle sequence rivers elsewhere. Hourly mean wind speeds of up to 65 km h−1 recorded at an automated weather station 25 km from the study site were found to suppress of the degree of thermal stratification in the study pool but did not achieve deep mixing of persistent seasonal thermoclines. Large, rapid and sustained air temperature decreases associated with the passage of cold fronts across southeastern Australia in summer were found to be more effective than wind and achieved mixing to depths of at least 4.2 m. Copyright © 2011 John Wiley & Sons, Ltd.
PHILharmonicFlows: towards a framework for object‐aware process management
Authors: Künzle Vera , Reichert Manfred 
Published: January 2011

AbstractCompanies increasingly adopt process management systems (PrMS) that offer promising perspectives for more flexible and efficient process execution. However, there still exist many processes in practice which are not adequately supported by contemporary PrMS. We believe that a major reason for this deficiency stems from the unsatisfactory integration of processes and data in existing PrMS. Despite emerging approaches that address this integration, a unified and comprehensive understanding of object‐awareness in connection with process management is still missing. To remedy this deficiency, we extensively analyzed various processes from different domains which are not adequately supported by existing PrMS. As a major insight we learned that in many cases comprehensive process support requires object‐awareness. In particular, process support has to consider object behavior as well as object interactions, and should therefore be based on two levels of granularity. Besides this, object‐awareness requires data‐driven process execution and integrated access to processes and data. This paper presents the basic properties of object‐aware processes as well as fundamental requirements for their operational support. It further introduces our PHILharmonicFlows framework which addresses these requirements and enables object‐aware process management in a comprehensive manner. Finally, we evaluate this framework along several process scenarios. We believe that a holistic approach integrating data, processes and users offers promising perspectives in order to overcome the numerous limitations of contemporary PrMS. Copyright © 2011 John Wiley & Sons, Ltd.