bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Detailed Validation Study of Multi-Environment Eulerian PDF Transport Method for Modeling Turbulent Non-Premixed Combustion
Authors: Yadav Rakesh , Kushari Abhijit , Eswaran Vinayak , Verma Atul K. 
Published: October 2013

PDF transport modeling has been known to be the most accurate for modeling turbulence chemistry interactions with finite rate chemistry effects. But, this is computationally very expensive. The Direct quadrature method of moments with Interaction by exchange with mean closure (DQMOM-IEM) can be a potential alternative to solve the PDF transport equation in an efficient manner.
The current work involves the validation of presumed shape multi-environment Eulerian PDF Transport method (MEPDF) using DQMOM-IEM approach for modeling turbulence chemistry interactions in non-premixed combustion problems. The joint composition PDF is represented as a collection of finite number of Delta functions. The PDF shape is resolved by solving the governing transport equations for probability of occurrence of each environment and probability weighted mass fraction of species and enthalpy in Eulerian frame for each environment. A generic implementation of the MEPDF approach is carried out for an arbitrary number of environments.
In the current work, the MEPDF approach is used for a series of problems to validate each component of MEPDF approach in an isolated manner as well as their combined effect. First of all, a non reactive turbulent mixing problem with two different Reynolds number (Re = 7000, 11900) is used for validation of the mixing and correction terms appear in the MEPDF approach. The second problem studied is a diffusion flame with infinitely fast chemistry having an analytical solution. The reaction component is validated by considering a 1D premixed laminar flame. In order to validate the combined effect of mixing and turbulence chemistry interactions, two different turbulent non premixed problems using global one step chemistry are used. The first reactive problem used is H2 combustion (DLR Flame H3) while the second reactive validation case is a pilot stabilized CH4 flame. The current predictions for all validation problems are compared with experimental data or published results. The study is further extended by modeling a turbulent non premixed H2 combustion using finite rate chemistry effects and radiative heat transfer. The current model predictions for different flame lengths as well as minor species are compared with experimental data. The current model gave excellent predictions of minor species like OH. The differences in the current predictions with experimental data are discussed.
Thermodynamic Optimization and Off-Design Performance Analysis of a Toluene Based Rankine Cycle for Waste Heat Recovery From Medium-Sized Gas Turbines
Authors: Carcasci Carlo , Ferraro Riccardo 
Published: October 2013

In the last years, the accelerated consumption of fossil fuels has caused many serious environmental problems such as global warming, the depletion of the ozone layer and atmospheric pollution. Similarly, low-temperature waste heat which is discharged in several industrial processes, contributes to thermal pollution and damages the environment. Furthermore, many industrial applications use low enthalpy thermal sources, where the conventional systems for the conversion of thermal energy into electrical energy, based on a Rankine water cycle, work with difficulty. Thus, the Organic Rankine Cycle can be considered a promising process for the conversion of heat at low and medium temperature whenever the conventional water cycle causes problems. Using an organic working fluid instead of water, the ORC system works like the bottom cycle of a conventional steam power plant. This kind of cycle allows a high utilization of the available thermal source. Moreover, the choice of the working fluid is critical, because it should meet several environment standards and not only certain thermophysical properties.
This paper illustrates the results for the simulations of an Organic Rankine Cycle based on a gas turbine with a diathermic oil circuit. The selected working fluid is toluene. The design is performed with a sensitivity analysis of the main process parameters, the organic Rankine cycle is optimized by varying the main pressure of the fluid at different temperatures of the oil circuit. The off-design is performed by varying the temperature of the air condenser.
Investigation of Outlet-Pressure Adaptation Mechanisms for Steam-Turbine Rotor Section
Authors: Amiri H. Beheshti , Piroozi A. A. , Kermani M. J. 
Published: October 2013

In this paper, employing an Eulerian-Eulerian method, based on a non-equilibrium point of view, the simulation of a two-phase vapor-liquid flow in the blade to blade passage has been numerically studied. In the following, the governing phenomena in blade to blade passage as well as important parameters in the blade design procedure have been investigated.
In the first section, after introducing the physical governing phenomenon in the subsonic and supersonic outflows, the mechanisms will be discussed which play a way more important role in changing the outlet pressure compared to the other less important ones. In the next section, the blade loading distribution, which is one of the most important parameters in designing the steam-turbine blades, has been studied. At the last part noting the significance of gas mass phase fraction on the blade surface, this parameter is comprehensively investigated. In order to perform a more successful analysis, the blade to blade passage has been simulated by a convergent-divergent nozzle. Taking into account the governing phenomena in the convergent-divergent nozzle and using the developed simulation model, most of experimental observations could be reproduced and also successfully understood.
Transpiration Boundary Conditions for a Steady Inverse Method
Authors: Yang Jinguang , Wu Hu 
Published: October 2013

Computational fluid dynamics has been widely used in the analysis of turbomachinery blades, however, its use as a design tool is far from sophisticated. The inverse method is such a design approach, which lends it self to the latter category. One application of the inverse method is the so called “pure inverse methd”, which differs from common analysis solver mainly in the boundary conditions on the blade surfaces. For this application, the usual non-penetration boundary conditions on the blade surfaces are aborted, instead, some aerodynamic constraints are imposed, and the flow is allowed to transpire through the actual solid wall. A camber line generation equation is added to periodically re-generate the blade camber line and drive the normal velocities on the blade surfaces to zero. When converged, the inverse method should obtain the blade shapes which satisfy the specified aerodynamic performance.
In the present paper, three transpiration boundary conditions for turbomachinery blades design are compared in terms of time cost, robustness, capability of coping separation flow etc. The first inverse boundary condition is based on the flow-tangency condition on the blade surfaces, the second relys on the propagating characteristics in the flow field, and the third is a hybrid version of the first and the second. The computation is validated for 2D Navier-Stokes equation. Two compressor cascades are taken as examples to compare the performance of the three transpiration boundary conditions. Finally some conclusions are drawn.
The Effect of Reduced Frequency on Transition and Separation at the Leading Edge of a Compressor Stator
Authors: Perkins Samuel C. T. , Henderson Alan D. 
Published: October 2013

Studies on the effects of stator reduced frequency in low pressure turbines have shown that periodic wake-induced unsteadiness can increase steady flow circulation by as much as 15% and reduce losses compared to a steady flow datum. A large separation bubble downstream of peak suction that formed under steady flow conditions was periodically suppressed by wake passing events, resulting in significantly reduced losses within the boundary layer.
This research extends this concept to a controlled diffusion compressor stator blade with a circular arc leading edge. The blade was placed inside a large scale, two-dimensional, cascade with a rotating bar mechanism used to simulate an upstream rotor blade row. The blade profile has been shown to experience leading edge separations and subsequent transition on both the pressure and suction surfaces due to a velocity overspeed caused by discontinuities in surface curvature.
Testing was carried out at reduced frequencies of 0.47, 0.94 and 1.88 at the design inlet flow angle 45.5° and Reynolds number based on chord of 230,000. The freestream turbulence intensity was 4.0%.
A range of experimental measurements were used to look at the blade’s performance: high resolution time-averaged blade surface static pressure measurements, inlet and exit 3-hole probe traverses and instantaneous, ensemble averaged and time average surface mounted hot-film measurements for the calculation of turbulent intermittency and quasi wall-shear stress.
Results showed that increasing the stator reduced frequency from, 0–1.88, increased the overall blade pressure loss. The losses generated by the pressure surface and suction surface differed significantly and are affected very differently. The pressure surface demonstrated a clear reduction in loss with an increase in reduced frequency whereas the opposite trend was seen on the suction surface.
Wake-induced turbulent strips suppressed the formation of leading edge separation bubbles that formed under steady flow conditions and in between wake passing events. Wake-induced turbulent strips reduced in width and level of turbulent intermittency through the favorable pressure gradients leading to peak suction and grew in the adverse pressure gradient of the velocity overspeed. The flow between wake-induced turbulent strips partially relaminarised through the favorable pressure gradient leading to peak suction.
Filtration of Gas Turbine Lube Fluid Using Anti-Static Filters
Authors: Farooq Khalid , Arwindekar Meghdoot S. 
Published: October 2013

Requirement for higher turbine performance and lower costs has resulted in smaller lubrication and control fluid systems operating at higher cleanliness levels, thus requiring higher fluid flux and finer filtration levels. Triboelectric Charge (TEC) generation by fine filters and its eventual discharge is considered to be a source of lubricating fluid breakdown and the resulting formation of resinous byproducts. These fluid breakdown byproducts form deposits or ‘varnish’ on the metallic surfaces causing servo-valve stiction along with other adverse consequences.
TEC generation occurs in fluid systems as a result of friction between the fluid and mainly the filtration media fibers. The friction causes charge separation between the filtration medium and the fluid, with the fluid oppositely charged to the filtration medium. The magnitude of charge generated depends on many interrelated factors, including the nature of the filter material and the fluid, fluid velocity, viscosity, conductivity and the contact area. The electrostatic discharge manifests itself in several ways, the most easily noticeable way being an audible clicking noise as the discharge of the accumulated electrostatic charge causes sparking internally within the system. In addition to lubricant degradation and varnish formation, the electrical charge can travel downstream with the fluid causing damage to system components, including the filter. There have been reports of heat exchanger damage, located downstream of the filters, due to the electrostatic charging of the fluid. The use of metal support meshes or other methods to dissipate the electrostatic charge to prevent its build-up in the filter cartridge may prevent the discharge within the filter assembly and the resulting filter damage, but it does not prevent the charging of the fluid, and the migration of the charge downstream causing damage to the fluid and the downstream components. In 2005 Pall Corporation introduced filter cartridges that mitigate charge generation and dissipate the small charge generated at its inception, thus offering the advantage of eliminating filter damage entirely, and significantly reducing the migration of the charge into the fluid and its associated damage to the fluid and the resulting varnish formation. This paper discusses the experience with the electrostatic charge dissipating filtration for the gas turbine lubrication application.
Numerical Simulation of the Aerodynamic Behavior of Propeller Blades at Subsonic Conditions
Authors: Farghaly Mohamed B. , El-Sayed Ahmed F. , Salem Galal B. 
Published: October 2013

The Organization of the Petroleum Exporting Countries (OPEC) oil crisis of the mid 1970s led to a revival in interest in the propeller as a possible fuel-efficient propulsion for aircraft operating at subsonic cruise speeds. A propeller aerodynamics is complex and should be analyzed carefully to ensure maximum propellers efficiency. Detailed knowledge of flow patterns and aerodynamics loads is necessary for blade material and manufacturing process.
In this study, an isolated propeller blade is chosen as the base of analysis, the geometry of the propeller: twist and chord variation with radius, are taken from real case module. The boundary conditions of the computational domain are set corresponding to that exist in the propeller manuals.
A three dimensional unstructured grid was generated and adopted using commercial grid generator GAMBIT software. The governing equations are solved using FLUENT6.3.26 a commercial CFD code, which uses a control volume approach on a grid over the computational domain. Results identified that the propeller efficiency, power coefficient are increases to reach maximum values and then decreases with increase Mach number. The thrust coefficient decreases with increase Mach number.
Fast B1 mapping based on interleaved‐three‐flip‐angle (ITFA) excitation
Authors: Kang Lae Hoon , Kim Dong Eun , Lee Soo Yeol 
Published: October 2013

Purpose:Fast B1 mapping based on short‐TR sequences is prone to T1‐induced errors. The purpose of this study is to develop a novel fast B1 mapping method that is less prone to T1‐induced errors.Methods:The authors acquired three gradient echoes by applying three RF pulses of different flip angles in an interleaved manner. The new method, named interleaved‐three‐flip‐angle (ITFA) method, employs a short TR for fast scan. Since the pixel intensity of the gradient echo images is dependent on both B1 and T1, the authors could compute a B1 map from the three gradient echo images with excluding the T1‐effects. The authors simulated the proposed B1 mapping method for various T1 values, and they found optimal flip angles for ITFA experiments for a given repetition time. To evaluate the B1 mapping performance, the authors made a human‐brain‐mimicking phantom that had six compartments with different T1 and T2. The authors performed B1 mapping experiments at 3T on the phantom and a volunteer using the ITFA method, the actual flip angle imaging (AFI) method, and the double angle method (DAM), and then, the authors compared the B1 mapping results.Results:Using a birdcage coil as a transceiver at 3T, the authors performed ITFA scans of the phantom and a volunteer with TR of 60 ms and the nominal flips angles of (25°, 70°, 80°). The authors also performed AFI scans with TR1/TR2 of 30/150 ms and the nominal flip angle of 60°. In both the phantom and human head imaging performed with the same scan times for ITFA and AFI, ITFA showed smaller average B1 errors than AFI when they were compared to DAM.Conclusions:ITFA excitations made it possible to reduce the T1‐effects on B1 mapping of the human‐brain‐mimicking phantom and the human brain at 3T. The authors expect the ITFA method can be used for B1 shimming once the optimal flip angles have been predetermined for the target imaging region and for the preferred TR.
An automated voxelized dosimetry tool for radionuclide therapy based on serial quantitative SPECT/CT imaging
Authors: Jackson Price A. , Beauregard Jean‐Mathieu , Hofman Michael S. , Kron Tomas , Hogg Annette , Hicks Rodney J. 
Published: October 2013

Purpose:To create an accurate map of the distribution of radiation dose deposition in healthy and target tissues during radionuclide therapy.Methods:Serial quantitative SPECT/CT images were acquired at 4, 24, and 72 h for 28177Lu‐octreotate peptide receptor radionuclide therapy (PRRT) administrations in 17 patients with advanced neuroendocrine tumors. Deformable image registration was combined with an in‐house programming algorithm to interpolate pharmacokinetic uptake and clearance at a voxel level. The resultant cumulated activity image series are comprised of values representing the total number of decays within each voxelˈs volume. For PRRT, cumulated activity was translated to absorbed dose based on Monte Carlo‐determined voxel S‐values at a combination of long and short ranges. These dosimetric image sets were compared for mean radiation absorbed dose to at‐risk organs using a conventional MIRD protocol (OLINDA 1.1).Results:Absorbed dose values to solid organs (liver, kidneys, and spleen) were within 10% using both techniques. Dose estimates to marrow were greater using the voxelized protocol, attributed to the software incorporating crossfire effect from nearby tumor volumes.Conclusions:The technique presented offers an efficient, automated tool for PRRT dosimetry based on serial post‐therapy imaging. Following retrospective analysis, this method of high‐resolution dosimetry may allow physicians to prescribe activity based on required dose to tumor volume or radiation limits to healthy tissue in individual patients.
Complete Genome Sequence of Pseudomonas aeruginosa Podophage MPK7, Which Requires Type IV Pili for Infection
Authors: Bae Hee-Won , Cho You-Hee 
Published: October 2013

ABSTRACT

We report the complete genome sequence of
Pseudomonas aeruginosa
podophage MPK7. It displays synteny to the
P. aeruginosa
phages of the
Phikmvlikevirus
genus, which includes phiKMV and LKA1. MPK7 requires type IV pili (TFP) for infection, suggesting the role of functional TFP as the receptor for this phage genus.
Draft Genome Sequences of Strains of Pasteurella multocida Isolated from the United Kingdom and the United States
Authors: Lainson Frederick A. , Dagleish Mark P. , Fontaine Michael , Bayne Colin , Hodgson J. Christopher 
Published: October 2013

ABSTRACT

Pasteurella multocida
is a major pathogen of farm animals and has worldwide distribution. Here we report the draft genome sequences of four strains that were isolated from animals in the United Kingdom and the United States and represent pathogenic and commensal presentation of the bacterium.
Interleukin 6 Stimulates Endothelial Binding and Transport of High-Density Lipoprotein Through Induction of Endothelial Lipase
Authors: Robert Jérôme , Lehner Marc , Frank Saša , Perisa Damir , von Eckardstein Arnold , Rohrer Lucia 
Published: October 2013

Objective—
In the reverse cholesterol transport pathway, high-density lipoprotein (HDL) passes the endothelial cell barrier by mechanisms involving the scavenger receptor class B type I and the ATP-binding cassette G1. However, little is known on how inflammation influences this transendothelial transport.

Approach and Results—

On stimulation with interleukin-6, cultivated primary endothelial cells showed increased binding and transport of
125
I-HDL without changing the expression of scavenger receptor class B type I and ATP-binding cassette G1. Therefore, we analyzed the involvement of endothelial lipase (EL), a known HDL-binding protein expressed by endothelial cells. Here, we show an increased EL expression after interleukin-6 stimulation. Moreover, using pharmacological inhibitors or RNA interference against EL, we demonstrated its participation in HDL binding and transport through the endothelium. Furthermore, adenovirus-mediated transfection of endothelial cells with either catalytically active or nonactive EL revealed that EL facilitates the endothelial binding and transport by both bridging and lipolysis of HDL. EL was also found responsible for the reduction of HDL particle size occurring during the specific transport through a monolayer of endothelial cells. Finally, pharmacological inhibition of EL reversed the inducing effect of interleukin-6 on HDL binding and transport.

Conclusions—
Interleukin-6 stimulates the translocation of HDL through the endothelium, the first step in reverse cholesterol transport pathway, by enhancing EL expression. In addition, we demonstrated the role of EL in the transendothelial transport of HDL.
Crucial Role for Endoplasmic Reticulum Stress During Megakaryocyte Maturation
Authors: Lopez Jose J. , Palazzo Alberta , Chaabane Chiraz , Albarran Letizia , Polidano Evelyne , Lebozec Kristell , Dally Saoussen , Nurden Paquita , Enouf Jocelyne , Debili Najet , Bobe Régis 
Published: October 2013

Objective—
Apoptotic-like phase is an essential step for the platelet formation from megakaryocytes. How controlled is this signaling pathway remained poorly understood. The aim of this study was to determine whether endoplasmic reticulum (ER) stress–induced apoptosis occurs during thrombopoiesis.

Approach and Results—

Investigation of ER stress and maturation markers in different models of human thrombopoiesis (CHRF, DAMI, MEG-01 cell lines, and hematopoietic stem cells: CD34
+
) as well as in immature pathological platelets clearly indicated that ER stress occurs transiently during thrombopoiesis. Direct ER stress induction by tunicamycin, an inhibitor of N-glycosylation, or by sarco/endoplasmic reticulum Ca
2+
ATPase type 3b overexpression, which interferes with reticular calcium, leads to some degree of maturation in megakaryocytic cell lines. On the contrary, exposure to salubrinal, a phosphatase inhibitor that prevents eukaryotic translation initiation factor 2α-P dephosphorylation and inhibits ER stress–induced apoptosis, decreased both expression of maturation markers in MEG-01 and CD34
+
cells as well as numbers of mature megakaryocytes and proplatelet formation in cultured CD34
+
cells.

Conclusions—
Taken as a whole, our research suggests that transient ER stress activation triggers the apoptotic-like phase of the thrombopoiesis process.
Converting and Not Converting “Strangers” in Early Modern London
Authors: Dimmock Matthew 
Published: October 2013

Abstract
The baptism of strangers in early modern England is often imagined as a “protocolonial” enterprise. This article explores the structure, contexts, and language of a number of “stranger” baptisms in this period to challenge such a reading. The improvisatory nature of these baptisms, a consequence of the lack of a specific service until 1662, is explored, with particular attention paid to language and structure, and the role of a Calvinist-influenced conception of religious and cultural difference. The article is also concerned with subaltern voices and silence. It concludes with a close examination of the circumstance of the baptizing of a “Turk” (initially named Chinano, then William) in London in 1586, considering the unique structure created for this specific occasion, and arguing that the occasion depends upon Chinano’s articulation of the reasons for his conversion before the community of believers to which he seeks access.