bluuebunny/crossref_metadata_2025_split huggingface dataset:
Experimental and Simulation Studies of Density-Driven-Convection Mixing in a Hele-Shaw Geometry with Application for CO2 Sequestration in Brine Aquifers
Authors: Taheri Amir , Torsæter Ole , Wessel-Berg Dag , Soroush Mansour 
Published: June 2012

Abstract
CO2 sequestration in deep formations is being actively considered for the reduction of greenhouse gas emissions. Saline aquifers are considered as one of the most favorable options for this purpose. It has been observed that dissolution of CO2 into brine causes increased density of the mixture. If the corresponding Rayleigh number of the porous medium is high enough to initiate convection flows, density-driven-convection happens and the rate of dissolution increases. Early time dissolution of CO2 in brine is mainly dominated by molecular diffusion while it will be accelerated by density-driven-convection. More contribution of dissolution mechanism for trapping of CO2 decreases the risk of leakage.
Density-driven-convection mechanism was investigated in a Hele-Shaw cell with colored-brine and fresh-water instead of CO2-diffusive layer and brine. A convective instability is created by colored-brine diffusing onto the surface of a fresh-water layer. For this configuration, density-driven-convection flow enhances the mass transfer rate of high density fluid into the low density one. The analysis is also done numerically with Eclipse reservoir simulation software. With this analysis, the effects of density-driven-convection on accelerating the rate of dissolution are investigated. Although the horizontal wavelength of the initial instability is small, an increase in the horizontal wavelength of the convective flow with time and depth is observed as the resulting two-dimensional convection develops. Effects of density of fluids and also dip of the systems on convection flows are studied here. Also the changes in geometry of the convection streams with depth and time are investigated. The results have important implications in dissolution trapping of CO2 in brine aquifers.
The Volund Field: Developing A Unique Sand Injection Complex In Offshore Norway
Authors: Townsley Ann , Schwab Anne M. , Jameson Eric W. 
Published: June 2012

Abstract
The Volund Field lies in the Norwegian sector of the North Sea (Block 24/9). It is successfully producing from a large-scale hydrocarbon-bearing sandstone injection complex in the Early Eocene section. The complex was identified from the seismic, which exhibits a Class 3 bright negative amplitude AVO anomaly. The first exploration well was drilled in 2004 on the Hamsun Prospect, and development drilling was completed in 2010. Volund Field is currently producing oil from four horizontal branches, with one water injector well.
Volund Field is unique in that the entire field is composed of a large-scale sandstone injection complex. The reservoir consists of a deeper central unit of stacked sandstone sills, which are surrounded by shallower, steeper dipping injected sandstone dykes (&gt;20°, often called ‘wings’). The injected sands are an excellent reservoir with consistently high porosity and permeability. Based on seismic, many of the steeply dipping injectites were expected to have good connectivity from the water leg through the oil leg and into the gas cap. However, pre-production the extent of aquifer support and efficiency of water sweep were unclear.
Geobodies were extracted from the seismic, based on the AVO anomaly exhibited by the hydrocarbon-filled injectite sands at Volund, and used to capture the geometry of the injectite within a reservoir geomodel. By populating these core bodies and surrounding "halos" with sands of varying properties, a series of realizations were built. Simulation modeling was employed to complete a dynamic uncertainty study and understand the potential effects of connectivity on aquifer and injection support. The four horizontal branches have now been successfully drilled using the seismic to give ~5500m of well control. Production began in April 2010 and has demonstrated that although the reservoir does benefit from aquifer support, water injection is required to maintain pressures at current production rates.
This Volund Field case study is an excellent, unique example of an economic producing sandstone injection complex.
Real Time Advanced Surface Flow Analysis for Detection of Open Fractures
Authors: Al-Adwani Talal , Singh Sunil , Khan Badruzzaman , Dashti Jalal , Ferroni Gionata , Martocchia Alberto , Estarabadi Javad 
Published: June 2012

Abstract
This paper presents a methodology which allows performing a real time characterization of the conductive natural fractures permeability intercepted by the bit while drilling. Such fractures are detected by monitoring continuously flowing from the wellbore into surrounding formations and the mud losses at the rig-site using flow-meters measuring both the ingoing and the outgoing mud flow.
Moreover, when drilling naturally fractured reservoirs, mud loss data provide one of the most effective means to assess the existence of conductive fractures intercepting the wellbore and therefore to identify potentially producing intervals.
The patterns in the variations of these volumes are analyzed to identify open fractures. The advanced Flowmeter has increased the resolution of the mud flow measurements. It has enabled the authors to assess the flow quantitatively and relate mud flow anomalies with the presence of open fractures down hole in the trial exploratory well.
The mud flow anomalies were validated with surface drilling parameters and gas indications. It was observed that the open fractures were associated with increase in torque and gas indication. The mud flow anomalies also provide crucial information for early kick or losses detection in high pressure gas wells because a better accuracy and a quicker response in detecting kicks and losses can be achieved by monitoring the changes of the mud flow rate by using flow meters measuring the inflow and the outflow mud rate, respectively.
Method and Theory The most commonly used techniques to detect the mud losses consist in monitoring the level of the mud pits with acoustic, floating sensors and/or using paddles set inside the flow line that measure the return mud flow rate with a small degree of accuracy. The traditional Flowmeter provides a simple qualitative fluctuation in mud flow. In contrast this advanced Flowmeter works on the principle of converting mudflow out in to an analog signal which represents the volume of mud.
Structural studies on different types of ferroelectric liquid crystalline substances
Authors: Obadović D. , Stojanović M. , Bubnov A. , Éber N. , Cvetinov M. , Vajda A. 
Published: June 2012

Structural studies on different types of ferroelectric liquid crystalline substances
Structural studies of ferroelectric liquid crystalline substances of different molecular structure have been reviewed. The discussion of the results deals mainly with the structure of chiral liquid crystals forming the smectic mesophase with ferroelectric order, as the research on ferroelectric liquid crystals, due to their high potential for application in electro-optics and photonics, has recently become one of the most attractive fields. Based on data of polarizing optical microscopy and X-ray diffraction obtained for unoriented samples we have identified the type of the mesophases, the temperature of the phase transitions and outlined the phase diagrams. An analysis of the relation between the molecular conformation and different types of phase transitions has been performed. The layer spacing and the average intermolecular distances have been determined for all studied phases from the positions of the small and the large angle diffraction peaks, respectively.
Adiabatic large polarons in anisotropic molecular crystals
Authors: Ivić Zoran , Pržulj Željko 
Published: June 2012

Adiabatic large polarons in anisotropic molecular crystals
We study the large polaron whose motion is confined to a single chain in a system composed of the collection of parallel molecular chains embedded in threedimensional lattice. It is found that the interchain coupling has a significant impact on the large polaron characteristics. In particular, its radius is quite larger while its effective mass is considerably lighter than that estimated within the one-dimensional models. We believe that our findings should be taken into account for the proper understanding of the possible role of large polarons in the charge and energy transfer in quasi-one-dimensional substances.
Evaluating Objective and Subjective Quantitative Parameters at the Initial Visit to Predict Future Glaucomatous Visual Field Progression
Authors: Ungar Allison K. , Wollstein Gadi , Ishikawa Hiroshi , Folio Lindsey S. , Ling Yun , Bilonick Richard A. , Noecker Robert J. , Xu Juan , Kagemann Larry , Mattox Cynthia , Schuman Joel S. 
Published: June 2012

BACKGROUND AND OBJECTIVE:
To evaluate the ability of structural assessment to predict glaucomatous visual field progression.

PATIENTS AND METHODS:
A total of 119 healthy eyes with suspected glaucoma and glaucomatous eyes with 5 or more optic nerve stereophotographs, optical coherence tomography (OCT), and confocal scanning laser ophthalmoscopy (CSLO) all acquired within 6 months of each other were enrolled. Odds ratios to predict progression were determined by generalized estimating equation models.

RESULTS:
Median follow-up was 4.0 years (range: 1.5 to 5.7 years). Fifteen eyes progressed by glaucoma progression analysis, 20 by visual field index, and 10 by both. Baseline parameters from stereophotographs (vertical cup-to-disc ratio and Disc Damage Likelihood Scale), OCT (global, superior quadrant, and inferior quadrant retinal nerve fiber layer thickness), and CSLO (cup shape measure and mean cup depth) were significant predictors of progression. Comparing the single best parameter from all models, only the OCT superior quadrant RNFL predicted progression.

CONCLUSION:
Baseline stereophotographs, OCT, and CSLO measurements may be clinically useful to predict glaucomatous visual field progression.
Divert to ULTRA: Differences in Infused Volumes and Clearance in Two On-Line Hemodiafiltration Treatments
Authors: Panichi Vincenzo , De Ferrari Giacomo , Saffioti Stefano , Sidoti Antonino , Biagioli Marina , Bianchi Stefano , Imperiali Patrizio , Gabbrielli Claudio , Conti Paolo , Patrone Pietro , Falqui Valeria , Rombolà Giuseppe , Mura Carlo , Icardi Andrea , Mulas Donatella , Rosati Alberto , Santori Francesco , Mannarino Antonio , Tomei Valeria , Bertucci Andrea , Steckiph Denis , Palla Roberto 
Published: June 2012

Background: Mixed diffusive-convective dialysis therapies offer greater removal capabilities than conventional dialysis. The aim of this study was to compare two different on-line, post-dilution hemodiafiltration (HDF) treatments with regard to achieved convective volume and middle-molecule dialysis efficiency: standard volume control (sOL-HDF) and automated control of the transmembrane pressure (TMP) (UC-HDF). Methods: We enrolled 30 ESRD patients (55.9 ± 14.0 years, 20/10 M/F) in a randomized, prospective, crossover study. The patients received a 3-month period of sOL-HDF followed by UC-HDF for a further 3 months, or vice versa, using the same dialysis machine. In sOL-HDF, fixed exchange volumes were set according to a filtration fraction greater than or equal to 25%. In UC-HDF therapy, the exchanged volume was driven by a biofeedback system controlling the TMP and its set point in a double loop. Patients maintained their treatment time, dialyzer, blood flow rate, and anticoagulant regimen unchanged throughout the study. Results: Greater convective volumes were achieved in UC-HDF than in sOL-HDF (23.8 ± 3.9 vs.19.8 ± 4.8 L; p<0.001) with high pre-dialysis Ht value (sOL-HDF 34.0 ± 4.5% and UC-HDF 34.0 ± 4.4%; p = 0.91). The average clearance values of β2m and P were higher in UC-HDF than in sOL-HDF (respectively 123 ± 24 vs. 111 ± 22 ml/min, p<0.002 and 158 ± 26 vs. 152 ± 25 ml/min, p<0.05). Moreover, the UC-HDF mode led to a significantly increased rate of call-free sessions from 88% to 97% (p<0.0001). Conclusions: This study showed that the biofeedback module, applied to the automatic control of TMP in on-line HDF, results in higher convective volumes and correspondingly higher β2m and P clearances. By making the HDF treatment more automated and less complex to perform, it significantly reduced the staff workload.
Direct adaptive neural tracking control for a class of stochastic pure‐feedback nonlinear systems with unknown dead‐zone
Authors: Wang Huanqing , Chen Bing , Lin Chong 
Published: June 2012

SUMMARYThis paper considers the problem of adaptive neural tracking control for a class of nonlinear stochastic pure‐feedback systems with unknown dead zone. Based on the radial basis function neural networks' online approximation capability, a novel adaptive neural controller is presented via backstepping technique. It is shown that the proposed controller guarantees that all the signals of the closed‐loop system are semi‐globally, uniformly bounded in probability, and the tracking error converges to an arbitrarily small neighborhood around the origin in the sense of mean quartic value. Simulation results further illustrate the effectiveness of the suggested control scheme. Copyright © 2012 John Wiley & Sons, Ltd.
Synthesis and Multiscale Evaluation of LiNbO3‐Containing Silicate Glass‐Ceramics with Efficient Isotropic SHG Response
Authors: Vigouroux Hélène , Fargin Evelyne , Gomez Sonia , Le Garrec Bruno , Mountrichas Grigoris , Kamitsos Efstratios , Adamietz Frédéric , Dussauze Marc , Rodriguez Vincent 
Published: June 2012

AbstractA study of bulk second harmonic generation (SHG) response of lithium niobium silicate glass‐ceramics is presented. The observed macroscopic SHG signals have an isotropic 3D nature. To interpret this particular nonlinear optical response, a multiscale approach is used in which clear correlations between structure and optical response are characterized from the sub‐micrometer to the millimeter scale. In particular, it is inferred that the radial distribution of the LiNbO3 crystallites in spherulite domains is at the origin of the isotropic bulk second order optical property. It is suggested that spherulitic crystallization in glass‐ceramic is a challenging method to elaborate isotropic nonlinear optical properties in inorganic materials.
Directing Osteogenesis of Stem Cells with Drug‐Laden, Polymer‐Microsphere‐Based Micropatterns Generated by Teflon Microfluidic Chips
Authors: Shi Xuetao , Chen Song , Zhou Jianhua , Yu Haijun , Li Lei , Wu Hongkai 
Published: June 2012

AbstractHuman bone tissue is built in a hierarchical way by assembling various cells of specific functions; the behaviors of these cells in vivo are sophisticatedly regulated. However, the cells in an injured bone caused by tumor or other bone‐related diseases cannot properly perform self‐regulation behaviors, such as specialized differentiation. To address this challenge, a simple one‐step strategy for patterning drug‐laden poly(lactic‐co‐glycolic acid) (PLGA) microspheres into grooves by Teflon chips is developed to direct cellular alignment and osteogenic commitment of adipose‐derived stem cells (ADSCs) for bone regeneration. A hydrophilic model protein and a hydrophobic model drug are encapsulated into microsphere‐based grooved micropatterns to investigate the release of the molecules from the PLGA matrix. Both types of molecules show a sustained release with a small initial burst during the first couple of days. Osteogenic differentiated factors are also encapsulated in the micropatterns and the effect of these factors on inducing the osteogenic differentiation of ADSCs is studied. The ADSCs on the drug‐laden micropatterns show stronger osteogenic commitment in culture than those on flat PLGA film or on drug‐free grooved micropatterns cultured under the same conditions. The results demonstrate that a combination of chemical and topographical cues is more effective to direct the osteogenic commitment of stem cells than either is alone. The microsphere‐based groove micropatterns show potential for stem cell research and bone regenerative therapies.
Multifunctional Magnetic Nanoparticles for Synergistic Enhancement of Cancer Treatment by Combinatorial Radio Frequency Thermolysis and Drug Delivery
Authors: Xu Yang , Karmakar Alokita , Heberlein Wolf E. , Mustafa Thikra , Biris Alexandru R. , Biris Alexandru S. 
Published: June 2012

AbstractFew‐layer, carbon‐coated, iron (C/Fe) magnetic nanoparticles (MNPs) were synthesized with controlled sizes ranging from 7 to 9 nm. The additional loading of two anti‐cancer drugs, doxorubicin and erlotinib, was achieved through – stacking onto the carbon shells. Controlled release of the drugs was successfully triggered by radio frequency (RF) heating or pH variation. Based on the experimental results, C/Fe MNPs act as heat‐inducing agents and are able to thermally destroy cancer cells when RF is applied. It was found that the combination of anti‐cancer drugs (in particular a low dose of doxorubicin) and RF treatment demonstrates a synergistic effect in inducing cell death in pancreatic cancer cells. Our findings demonstrate that MNPs can be used as highly efficient multimodal nanocarrier agents for an integrated approach to cancer treatment involving triggered delivery of antineoplastic drugs and RF‐induced thermal therapy.
Rheology of long‐chain branched polypropylene copolymers
Authors: Zulli Fabio , Andreozzi Laura , Passaglia Elisa , Augier Sylvain , Giordano Marco 
Published: June 2012

AbstractIn this work, we provide more insight into the rheological properties of functionalized polypropylene copolymers with modified architectures, which originate long‐chain branching. The evaluation of the average distance between branches and the fraction of long‐chain branch points has been carried out quantitatively, by numerical fitting of experimental data according to a literature model, and the viscoelastic response of the samples has been analyzed in terms of a Carreau‐Yasuda‐like model and Cole–Cole plots. These analyses allowed us to discriminate the viscoelastic behavior of the samples on the basis of their feed composition. Moreover, we were able to highlight direct correlations between viscosity, long‐chain branching level, distance between branching points and functionalization degrees of PP polymers. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Morphological Studies of Lymphatic Labyrinths in the Rat Mesenteric Lymph Node
Authors: Jia Limin , Xie Zunjiang , Zheng Jinhua , Liu Li , He Yan , Liu Fu , He Yechun 
Published: June 2012

AbstractTo supplement and correct the morphological features of lymphatic labyrinths (LLs) in rat mesenteric lymph node, the distribution, morphology and origin of LLs, and cellular elements in LLs, particularly the organization and integrity of the wall of LLs were examined by silver impregnation, transmission electron microscopy (TEM), scanning electron microscopy (SEM), and immunohistochemistry. LLs consisted of labyrinthine tubules and ran through not only the periphery of the deep cortical unit (DCU) but interfollicular cortex. LLs originated at the edge of the center of the DCU and of the follicle. At the site of their origin, the fibers in the wall of LL were continuous with the fibers located in the follicle and the center of DCU. The wall of LLs was a trilaminar membrane: a layer of flattened lymphatic endothelium; a layer of fibroblastic reticular cells; and amorphous substance and collagen fibers sandwiched between the above two layers. Under SEM and TEM, the whole amoeboid lymphocytes were moving through the pores in the wall of LL, which showed that lymphocytes end their journey through the paracortical cord by migrating into LLs. Immunohistochemical lymphatic vessel endothelial hyaluronan receptor‐1 expression was present in cells lining the LLs and intraluminal stellate cells, which may belong to the “sinus endothelial/virgultar cells.” LLs are specific channels that are different from lymphatic sinuses. LL may be regarded as a special part of lymphatic vascular system in lymph nodes. We confirm that LLs are important transport pathway of lymphocytes in lymph nodes. The structural framework of LLs facilitates the migration of lymphocytes. Anat Rec, 2012. © 2012 Wiley Periodicals, Inc.
Local Quadratic Model Tree with Orthogonal Matching Pursuit (LOQUMOTOMP) Method for Nonlinear System Identification
Authors: Ahmadi Salman , Karrari Mehdi 
Published: June 2012

AbstractIn order to accurately model the behavior of nonlinear systems under different operating conditions, complex structures, such as the Volterra and Wiener series', are often used. The main drawback of such structures is the need for a large number of parameters. In an alternative approach, the input‐output relation of such complex nonlinear systems is described using different local linear models under different operating conditions. Such models also require many local models to maintain the accuracy under different operating conditions. In this paper, both methods are combined and a new iterative method is presented to obtain an accurate model with fewer parameters. To create a more precise model, a choice is made at each iteration of the identification algorithm between increasing the number of local models and increasing the complexity of each local model. Furthermore, to reduce the number of parameters and local models, the most significant regressors are selected by an orthogonal matching pursuit method. In the method proposed, polynomial or linear structure is used for the operating condition of the nonlinear system with more or less complexity. The proposed method has been tested on the experimental data of a hydraulic actuator. The proposed identification method provides a more precise model with fewer parameters than some well‐known nonlinear system identification methods, such as neural networks and the Local Linear Model Tree (LOLIMOT).